DE102020112283A1 - PROCEDURE AND TESTING APPARATUS FOR TESTING A WIRING HARNESS - Google Patents

Abstract

The present invention relates to a method for testing a cable harness (104), wherein a strand (106) of the cable harness (104) is tested by a first interface (110) of the strand (106) and an opposing second interface (112) of the strand (106), a test signal (122) is sent from the first interface (110) to the second interface (112) via at least one wire (108) of the strand (106) and in response to receiving the test signal (122) ) a signal for controlling a predetermined action is provided at the second interface (122).

Description

Technical area

The present invention relates to a method and a test device for testing a wire harness.

State of the art

The present invention is described below mainly in connection with cable harnesses for vehicle electrical systems. However, the invention can be used for any application in which cable harnesses are produced.

A cable harness is a component in which, in particular, electrical lines of a vehicle are bundled. The wiring harness is pre-assembled outside the vehicle in order to largely avoid pulling in individual lines during the manufacture of the vehicle. The lines of the wiring harness can have different lengths. The cable harness usually has branches at which one or more lines branch off and / or open laterally. In sections between the branches, the lines run essentially parallel and are bundled, for example, by a wrapping of adhesive tape.

During the production of the cable harness, the individual lines or also pre-bundled sub-bundles of the cable harness are arranged, aligned and bundled in the parallel sections on a building board in accordance with a construction specification for the cable harness. Interfaces can be arranged on at least some of the ends of the lines and connected to the cable harness. The ends of lines that end in common can be combined in common interfaces.

After production, the cable harness is removed from the building board and electrically tested at a test station by connecting the interfaces to the corresponding adapters of a test device. Contact elements of the adapter contact the individual lines of the respective interface. Each contact element of each adapter is connected to test electronics of the test device via its own test line. Each line is connected to two contact elements from different adapters. The line thus forms part of a test circuit of the test electronics. The test circuits are individually energized for the electrical test and thus checked for continuity.

Description of the invention

One object of the invention is therefore to provide an improved method and an improved test device for testing a cable harness using means that are as simple as possible in terms of construction.

The object is achieved by the subjects of the independent claims. Advantageous developments of the invention are given in the dependent claims, the description and the accompanying figures. In particular, the independent claims of one claim category can also be developed analogously to the dependent claims of another claim category.

The approach presented here can drastically reduce the amount of wiring required for a test device for testing a cable harness. As a result, the test device can be at least partially integrated into a building board for producing the cable harness. Interfaces of the cable harness can thus be connected to corresponding adapters of the test device during manufacture and the cable harness can be checked for errors during manufacture. Any errors found can be corrected while the wiring harness is still arranged on the building board.

A method for testing a cable harness is proposed, a strand of the cable harness being tested by contacting a first interface of the strand and an opposite, second interface of the strand, a test signal from the first interface to the second interface via at least one wire of the strand is sent and in response to receiving the test signal at the second interface, a signal for controlling a predetermined action is provided.

Furthermore, a testing device for testing a cable harness is proposed, the testing device having at least one strand testing group for testing a strand of the cable harness, the strand testing group having a primary adapter for contacting a first interface of the strand and a relay device connected to a secondary adapter for contacting a second interface of the strand having, wherein the primary adapter is connected to an evaluation device of the test device, wherein the evaluation device is designed to send a test signal to the relay device using the primary adapter and the secondary adapter via at least one wire of the strand and the relay device is designed to respond to the Test signal to execute or control a predetermined action.

Furthermore, a building board with a test device according to the approach presented here is proposed, the primary adapter being arranged in the area of an intended position of the first interface, in particular above the building board, and the secondary adapter being arranged in the area of an intended position of the second interface, in particular on the building board.

A cable harness can be understood to mean a cable harness for a vehicle. The cable harness can have multiple cables. The cables can be of different lengths. The cables can be bundled at least in sections to form cable bundles. The wiring harness can be made on a building board. The building board can have partial areas that are separate from one another. On the building board, receptacles for the cables can be arranged along paths of the cables that are defined by a construction plan of the cable harness. The recordings can, for example, be fork-shaped and lead the cables hanging freely over the building board. The cables can be cut to the intended length and inserted into the receptacles.

A strand of the cable harness can be understood as a functional unit of the cable harness. The strand has at least one cable with at least one wire. The wire is an electrical single conductor in the cable that extends from one end of the cable to the other end of the cable. A sheath of the cable surrounds the core and isolates the core from other cables. The wire can be composed of several strands or designed as a single wire. The cable can also be multi-core, that is to say it can have several cores which are electrically insulated from one another when designed as intended and which are encased by a common sheath.

The strand can also comprise several cables. The cables of a strand have a common starting point and a common end point. If the strand runs without parallel cables from another strand, the cables of the strand can be bundled into a separate cable bundle. If several strands run in parallel, all cables can be bundled into a common cable bundle.

The strand can have interfaces at its starting point and at its end point. The interfaces are components at which the at least one cable of the line ends. If the interface is designed as intended, the cable is anchored in the interface. When properly connected to the interface, the at least one wire is electrically conductively connected to a contact point of the interface. The interface can have one or more contact points per wire. In the case of different cable harnesses, the contact point of the wire can be arranged at the same contact position in the interface if the cable harnesses are designed as intended. The contact position can have a unique identifier. For example, the contact position can have a unique number and / or a unique name.

If the interface is designed as intended, the interfaces can be designed to be media-tight. The interfaces of the line can be designed differently. The interfaces can be designed to be pluggable or screwable. Designed as plug connections, the interfaces of the line can each be designed as a plug or socket. Contact points of the plug-in interfaces can be designed as pins, for example. If several strings have a common starting point or end point, the interfaces of several strings can be combined in a multi-core component.

A line can have one or more branches to further interfaces. The branch can also be designed as at least one at least one-core cable. The at least one wire of the branch is electrically conductively connected to the corresponding wire of the line when it is designed as intended. The branch can be referred to as a splice.

An evaluation device can have test electronics of the test device. The evaluation device can be arranged centrally. The evaluation device can be divided into a small number of sub-evaluation devices in order to achieve a shorter line length. The test device can have a relay device for each core of the strand to be tested.

An adapter can be a counterpart to an interface. The adapter can be designed as a primary adapter in which at least all essential contact points of the interface of the string to be tested are connected to the evaluation device. The adapter can be designed as a secondary adapter in which at least the essential contact points of the interface of the string to be tested are each connected to a relay device.

The relay device can be controlled by the evaluation device via test signals. A test signal can represent a command to carry out an action. The relay device can be arranged in a decentralized manner. The relay device can be arranged spatially separated from the evaluation device. The relay devices of the test device can be distributed over the building board be arranged. In particular, the relay device can be arranged in the area of the secondary adapter assigned to it. The relay device can be attached to the building board. The evaluation device can send test signals to the corresponding relay device via the assigned wire. The relay device can receive and execute the test signals if the line is designed as intended. If, for example, a contact point of a wire is incorrectly positioned at one of the interfaces of the strand, the intended relay device cannot be activated via this wire, since the test signal does not arrive.

The relay device can be supplied with electrical energy via the wire to carry out the action. The relay device can, for example, pick up a voltage potential between two wires of the strand.

As an action, a response signal can be sent in response to the test signal. A response signal can contain information about the relay device. For example, the response signal can contain an identifier of the relay device. The response signal can also map at least one electrical value detected by the relay device. For example, the response signal can contain a value of an electrical voltage that can be measured on the secondary adapter.

A contact position of the wire at the second interface can be encoded and sent in the response signal. The relay device can be assigned to a specific contact position. If the relay device reads in a test signal via a wire connected to this contact position, the relay device can send back an identifier assigned to it in the response signal. If the identifier received by the evaluation device matches an expected identifier, the wire is being contacted as intended. If the received identifier does not correspond to the expected identifier, the contacting of the wire is faulty.

The response signal can be sent as an electrical signal via a circuit containing the wire. The response signal can therefore be sent directly over the wire in the opposite direction to the test signal. The circuit can be closed via a ground connection of the relay device and the evaluation device. Alternatively, the circuit can be closed via another wire in the line. An electrical current can flow in the circuit. The evaluation device can be a current source of the circuit. The relay device can be a consumer in the circuit. The relay device can be supplied via the electrical circuit. The test signal and the response signal can be modulated onto a voltage in the circuit.

The response signal can be sent as a light signal. For this purpose, the relay device can have a controllable light source. The evaluation device can have a camera. Light signals from several relay devices of the test device can be read in simultaneously via the camera. The light signal can be transmitted without contact. The light signal cannot be affected by electrical interference within the wiring harness. The light signal can, for example, be provided in a pulse-coded manner. As an alternative or in addition, the light signal can be color-coded and / or provided in a pattern-coded manner using a plurality of light sources. The light signal can also be perceived directly by the staff on the building board and a signaled error can be rectified immediately.

As an action, a control signal for an actuator can be provided in response to the test signal. A sequence of control signals can also be provided. For example, a locking or unlocking of the secondary adapter driven by the actuator can be controlled.

The second interface can be pressurized in response to the control signal. The secondary adapter can have a pressure connection for compressed air. A valve of the pressure connection can be activated by the activation signal in order to put the interface and the secondary adapter under pressure. Under pressure, leaks in the second interface can be easily identified, for example, by a noise flowing out of air.

The pressure in the housing can be monitored and represented in an electrical pressure signal. The secondary adapter can have a pressure sensor. The pressure sensor can be connected to the relay device. The pressure signal can be mapped in the response signal of the relay device. The relay device can also carry out a comparison of the pressure with an expected pressure and map a result of the comparison in the response signal. The pressure can be monitored over a period of time, especially when the valve is closed. Small leaks in the second interface can also be detected by several pressure measurements.

The relay device can also be connected to the evaluation device in an electrically conductive manner via a ground contact. The ground contact can be integrated into the building board, for example. The ground contact can be the only return line of the Be relay device. Due to the ground contact, point-to-point wiring of the relay device can be dispensed with.

The relay device can be arranged in a housing of the secondary adapter. The relay device can be integrated into the housing. As a result of the integration, the relay device and the secondary adapter can be preassembled and quickly and easily arranged on the building board. If the length of the string changes, the housing can simply be moved on the building board. If the second interface is changed, a suitable secondary adapter with a suitable relay device can be used quickly and easily.

The testing device can have at least one further strand testing device for contacting a further strand of the cable harness. Several strands of the cable harness can be checked at the same time with several string testing devices.

Figure list

• 1 eine Darstellung eines Baubretts mit einer Prüfvorrichtung gemäß einem Ausführungsbeispiel;
• 2 eine Darstellung einer Ader eines Strangs eines Kabelbaums mit einer Prüfvorrichtung gemäß einem Ausführungsbeispiel; und
• 3 eine Darstellung einer für lange Adern konfigurierte Auswerteeinrichtung einer Prüfvorrichtung gemäß einem Ausführungsbeispiel.

An advantageous exemplary embodiment of the invention is explained below with reference to the accompanying figures. Show it:

• 1 a representation of a building board with a test device according to an embodiment;
• 2 a representation of a wire of a strand of a cable harness with a test device according to an embodiment; and
• 3 a representation of an evaluation device configured for long wires of a test device according to an embodiment.

The figures are merely schematic representations and only serve to explain the invention. Elements that are the same or have the same effect are provided with the same reference symbols throughout.

Detailed description

For easier understanding, the reference numerals are assigned to the in the following description 1-3 retained for reference.

1 shows a representation of a building board 100 with a testing device 102 according to an embodiment. On the building board 100 becomes a harness 104 assembled or manufactured. The wiring harness 104 exhibits several strands 106 with different numbers of wires 108 on. Every strand 106 has a first interface at its beginning 110 and at its end a second interface 112 on. The first interface 110 and the opposite second interface 112 are thus at opposite ends of the strand 106 arranged. The strands are in partial areas that run parallel to one another 106 bundled. For example, the strands are wrapped with an adhesive tape and, as an alternative or in addition, encased by a protective tube.

The testing device 102 has a central evaluation device 114 on. The evaluation device 114 is via one or more primary adapters 116 the testing device 102 with approximately all wires 108 of the wiring harness 104 tied together. The primary adapters 116 are with the first interfaces 110 connected and contact all wires 108 in the respective interface 110 . Every vein contacted 108 is at the other end via a secondary adapter 118 with its own relay device 120 tied together. The secondary adapters 118 are with the second interfaces 112 connected and contact all wires 108 in the respective interface 112 .

One for each number of wires 108 per strand 106 corresponding number of relay devices 120 , one to the second interface 112 of the strand 106 adapted secondary adapter 118 and a primary adapter 116 can be used as a strand test group for the relevant strand 106 are designated. The wiring harness 104 has six strands here 106 on. The testing device 102 is designed to do five of the strands 106 to be tested and therefore has five strand test groups.

In one embodiment, the first are interfaces 110 of three of the strands 106 to a single interface 110 summarized. The primary adapters are accordingly 116 for contacting the wires 108 of the corresponding strands 106 also to a single primary adapter 116 summarized. The one in the interface 110 combined strands 106 have a different number of cores 108 on.

To the single strand 106 The first interface to check will be the wiring harness 110 of the strand in question 106 and an opposite second interface 112 of the strand in question 106 using the appropriate primary adapter 116 and secondary adapter 118 contacted. At least one vein 108 of the strand 106 then becomes a test signal 122 from the evaluation device 114 to the relay device connected to the wire 120 sent. The relay device 120 then performs in response to the test signal 122 take a predetermined action.

In one embodiment, the relay device transmits 120 a response signal 124 to the evaluation device 114 . In the response signal can different information can be coded. For example, in the response signal 124 an identifier of the responding relay device 120 be coded. This allows the evaluation device 114 decode which of the relay devices 120 on the test signal 122 answered.

The relay device 120 can also be an electrical voltage between an electrical potential of the wire 108 and measure a reference potential and in the response signal 124 encode. The evaluation device can thus decode how high a voltage drop in the conductor is 108 is. The reference potential can, for example, be a ground potential 126 of the building board 100 be. The reference potential can also be an electrical potential of another wire 108 of the same strand 106 be.

When the relay device 120 and the evaluation device each have a ground contact 126 have and are connected to the same ground potential, an electrical circuit for supplying the relay device 120 over the vein 108 and the ground potential are closed. The relay device 120 can alternatively by a circuit with two wires 108 of the same strand 106 are supplied.

In one embodiment, the relay device transmits 120 the response signal 124 as an electrical signal via the wire 108 to the evaluation device 114 . Alternatively or in addition, the response signal 124 sent as an electromagnetic signal. For example, the relay device 120 at least one signal lamp 128 have over which the response signal 124 is emitted as a light signal.

In one embodiment, the relay device 120 in response to the test signal 122 a control signal 130 for one actuator 132 of the secondary adapter 118 ready. The actuator 132 can, for example, an internal pressure of the second interface 112 and the secondary adapter 118 increase to a pressure test of the second interface 112 perform. The internal pressure can be measured by a pressure sensor on the secondary adapter 118 can be recorded and mapped in a pressure value. The relay device 120 can be the pressure value in the response signal 124 encode.

2 shows a representation of a wire 108 of a strand 106 a wiring harness 104 with a testing device 102 according to an embodiment. The testing device 102 essentially corresponds to the test device in 1 . In contrast to this, symbolically there is only one vein 108 of the wiring harness 104 shown. The evaluation device 114 is designed here as a microcontroller. The evaluation device 114 can be called a master. The evaluation device 114 assigns a send path 200 for sending the test signal 122 and a receive path 202 to receive the response signal 124 on. The send path 200 and the receive path 202 are with the vein 108 tied together.

The relay device 120 has an integrated circuit with a transmission path 200 and a receive path 202 on. The send path 200 and the receive path 202 are with the vein 108 tied together. The relay device 120 can be referred to as a slave. The relay device 120 receives using the receive path 202 that about the vein 108 sent test signal 122 and sends using the send path 200 in response to the test signal 122 the response signal 124 over the vein 108 return. The send path 200 is designed as a transistor that sends the response signal 124 using a voltage potential between the wire 108 and a ground contact 126 the relay device on the wire 108 imprints.

3 shows a representation of one for one long vein 108 configured evaluation device 114 a test device 102 according to an embodiment. The evaluation device 114 essentially corresponds to the evaluation device in 2 . In addition to that, here is a driver 300 between the microcontroller and the wire 108 arranged. The driver 300 amplifies the test signal 122 and the response signal 124 for the microcontroller. To do this, the driver 300 its own power supply against its own ground contact 126 on.

In other words, an addressable test pin and a communication-based test concept are presented.

In the process of creating a customer-specific cable harness (KSK), the cable harness is typically assembled / completed on building boards, then removed from the building board, transported to a central test station, laid on, spread out again, all plugs plugged in and then an end-of-line (EOL) test carried out. After a successful test, the now tested cable harness is disconnected again, put together and transported to the packing station. In order to save (unproductive) handling and transport steps, the attempt is made to relocate the testing of the cable harness to the building board. This concept is contradicted by the fact that a relocation of test points (test adapters) to the building boards is always accompanied by a multiplication of the number of test adapters and complex wiring on the building board. The wiring is complex because each pin in each adapter requires wiring to a central test station or multiplexer / interface card.

So far, current has been injected into the lines of the customer-specific cable harness and sensed at the other end of the customer-specific cable harness. This requires complex wiring to central test electronics.

In the approach presented here, the test is designed in such a way that a simplification of the electrical structure and the wiring of the test adapter to the outside (to a test system) is achieved in terms of complexity and costs, so that a large number of adapters can be placed on the building board economically and with regard to . of handling makes sense.

The pin-by-pin wiring of each adapter to the test station is reduced by the fact that the lines of the customer-specific wiring harness are no longer tested with a driver / comparator concept, but rather using information transmitted on the customer-specific wiring harness, such as analog measured values or digital information such as ID numbers. Only one end (the “active” end) of the customer-specific cable harness has pin-by-pin wiring to the test station. The other end of the customer-specific wiring harness is coded pin by pin (in the adapter). The coding is queried via the lines of the customer-specific cable harness from the active end, the data exchange (successful and / or unsuccessful) is the actual test. The communication content contains the information about the structure of the network.

The approach presented here results in cost savings by reducing the number of complex test adapters. Furthermore, there is a potential for simplifying the creation process of the customer-specific cable harness by integrating tests into a manufacturing process on the building board. Furthermore, there is a potential to reduce handling and transport steps.

The approach presented here enables a reduction in the amount of wiring from the test adapter to the test station. This results in a cost saving and a reduction in complexity. As a result, it is possible to move a large number of test adapters away from the test system (e.g. on the building board). The network or the cable harness can be checked using unique pin addresses. It is possible to carry out several tests in parallel.

In order to avoid the pin-by-pin wiring to the central test electronics, which is necessary for a driver / comparator-based test, one end of the line (the "passive" end) is electronically coded pin-by-pin in the adapter and the other end (the "active" line end) conventionally connected to a central test station. The "active" end offers the possibility of querying the coding (s) of the passive end via the line of the customer-specific cable harness.

The pin-by-pin coding on the passive line end can be carried out with clearly distinguishable complex terminations (RLC combinations), whereby it can be difficult to clearly differentiate the combination of connections, e.g. with splice connections.

It is more advantageous to terminate the passive cable ends with digitally addressable components. There are components that draw or generate their supply voltage via a line ("1-Wire"), communicate with a "master" on this line and have a unique "address". Some of these modules are "multidrop-capable", i.e. several "slaves" can communicate with a master via just one line (e.g. in line networks, splice). In addition to the signal line, ie the line of the customer-specific cable harness to be tested, the only other connection between the building board and the test station is a ground line to the test station.

"1-Wire" modules with a non-volatile memory (EEPROM, OTP) can also be programmed with meaningful data (e.g. connector name, chamber number) when the test adapter is created or initialized. This information can be queried by the test station via the active line end of the customer-specific cable harness during the test process. The data exchange between the active end of the customer-specific cable harness (= master) and the passive end (s) of the customer-specific cable harness is then the actual test. The communication content between the master and its slave (s) contains information about the structure of the network.

Possible application scenarios for 1-wire based communication components in the test environment are described below.

The test station behaves functionally similar to the customer-specific wiring harness as the customer-specific wiring harness is used later in the vehicle. To put it simply, there are a few / few active / intelligent components alias "masters" in the vehicle, such as control units where many lines merge and many more passive components alias "slaves", such as sensors with few lines / nodes.

The test station presented here primarily serves the "master" interfaces of the customer-specific cable harness via complex adapters. The "slave" interfaces are "closed" with "passive" / self-sufficient test adapters. The “intelligence” of the slave adapters is functionally minimally reduced to such an extent that they react in a defined manner to stimuli coming from the master side. For example, the slave adapters can respond or start an action. The interface between the passive adapter and the test station is minimalist.

As many test adapters as possible are only designed as "slave" adapters, which leads to cost savings through the approach presented here.

The simple interface between a "slave" adapter and the test station can be flexibly placed decentrally on the building board or piggyback.

Complex test tasks can be carried out using the small number of “master” adapters. The test tasks can be controlled centrally in the test station.

Pins in “slave” adapters are terminated with 1-wire addressable modules. The communication between a "master" adapter and its slave (s) takes place similar to the function in the vehicle via the lines of the customer-specific cable harness. Communication is also the test. If the contacts are open, the master will not find any communication partners. The master “sees” branches or splices on the basis of the subscriber identification in its communication stream (multi-drop).

In the event of short circuits between lines / networks, slave terminations appear in the communication stream of another master where they should not be. At the end of the test sequence, a list of “slave” pins can be created for each “master” pin that have been successfully found on the assigned communication line (line of the customer-specific cable harness). If the 1-wire slaves are designed as 1-wire EEPROM, a unique coding such as connector designation and chamber can be "flashed" for each test pin when the test adapter is created. This can be queried in the communication protocol of the master. This means that a list of the communication partners on each line of the customer-specific cable harness can be created immediately.

Components can be designed with a parasitic feed. There is no local supply with a supply voltage Vcc. The supply voltage Vcc is provided or “stolen” from the data line. The component has at least the data line and a GND connection as connections. In the case of parasitic supply, the number of slaves (splice in the customer-specific cable harness) per bus can be limited to less than 30. In addition, the buses or the lines of the customer-specific cable harness can have a high intrinsic capacitance.

Addressable spring pins in "passive" test adapters can be monitored using modules with two connections, for example with the TO-92 housing or flip chip, e.g. module DS2401.

Addressable spring pins with an additional status query e.g. B for switch pins can be monitored using modules with three or four connections for the input signals, for example with the housing form TSOC, TDFN, e.g. as a module DS2413. This means that the network analysis can be carried out with a query of (two) signal states (e.g. on the switch pin).

Cable forks with a status query can also be used.

Alternatively, components can be implemented with a local Vcc supply. The component has at least three connections. The connections are the data line, a voltage supply for Vcc and a ground contact or GND connection. In addition, there can be two connections for digital I / O, for example. With local supply, more complex bus structures or longer bus lines of the customer-specific cable harness can be operated in a stable manner.

Addressable spring pins with additional I / Os can be used as output 28V; Drive 20mA and e.g. switch a pneumatic valve

More complex functions, such as B. A / D conversion or pressure testing with a cheap controller (4bit, 8bit) can be integrated in an adapter. The controller can also emulate a 1-wire slave. Due to the local supply, (two) signals up to 28V; 20mA can be switched. For example, pneumatic valves or LEDs can be activated.

Multi-pole adapters with complex functions can be arranged in vertical module panels in the middle above the building board.

Simple adapters (low-pole up to 16pins), with or without basic functions, can be added to the building board (e.g. piggyback) or can be part of the building board.

In summary, complex “master” adapters can be brought up to the building board from above in a central station. Simple "slave" adapters can, for example, be brought up to the building board from below as piggybacks using AGVs and connected to the building board in a wedding. The test can be carried out communicatively, as there is a maximum of one Vcc and / or GND connection between the Piggyback and the PST.

Since the devices and methods described in detail above are exemplary embodiments, they can be modified in the usual way by a person skilled in the art to a wide extent without departing from the scope of the invention. In particular, the mechanical arrangements and the proportions of the individual elements to one another are selected merely as examples.

List of reference symbols

100

Building board

102

Testing device

104

Wiring harness

106

strand

108

Vein

110

first interface

112

second interface

114

Evaluation device

116

Primary adapter

118

Secondary adapter

120

Relay device

122

Test signal

124

Response signal

126

Ground contact

128

Signal lamp

130

Control signal

132

Actuator

200

Send path

202

Receive path

300

driver

Claims (10)

Method for testing a cable harness (104), wherein a strand (106) of the cable harness (104) is tested by contacting a first interface (110) of the strand (106) and an opposite second interface (112) of the strand (106) , a test signal (122) is sent from the first interface (110) to the second interface (112) via at least one wire (108) of the strand (106) and in response to receiving the test signal (122) at the second interface (122 ) a signal for controlling a predetermined action is provided. Procedure according to Claim 1 , in which the sending of a response signal (124) is triggered as an action. Procedure according to Claim 2 , in which a contact position of the wire (108) at the second interface (112) is sent encoded in the response signal (124). Method according to one of the Claims 2 until 3 , in which the response signal (124) is sent as an electrical signal via a circuit containing the wire (108) or as a light signal. Method according to one of the preceding claims, in which an actuator (132) is controlled as an action using a control signal (130). Procedure according to Claim 5 , in which the second interface (112) is put under pressure in response to the control signal (130). Test device (102) for testing a cable harness (104), wherein the test device is configured to carry out or control the method according to one of the preceding claims. Test device (102), in particular after Claim 7 for testing a cable harness (104), the testing device (102) having at least one strand testing group for testing a strand (106) of the cable harness (104), the strand testing group having a primary adapter (116) for contacting a first interface (110) of the strand (106) and a relay device (120) connected to a secondary adapter (118) for contacting a second interface (112) of the strand (106), the primary adapter (116) being connected to an evaluation device (114) of the test device (102) , wherein the evaluation device (114) is designed to send a test signal (122) to the relay device (120) using the primary adapter (116) and the secondary adapter (118) via at least one wire (108) of the strand (106) and the relay device (120) is designed to provide a signal for triggering a predetermined action in response to the test signal (112). Test device (102) according to Claim 8 , in which the relay device (120) is furthermore connected to the evaluation device (114) in an electrically conductive manner via a ground contact (126). Test device (102) according to one of the Claims 7 until 9 , with at least one further strand testing device for contacting a further strand (106) of the cable harness (104).

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