FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Faulty Signal






Faulty signal

Checking for permanent or intermittent faults
Unlock the car using the key or remote control from outside.

Does the general interior lighting come on?

Yes - Intermittent fault

No - Checking for a short-circuit

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Checking for a short-circuit
Check that the button has not jammed in its depressed position.
Check the cable between control module terminal #16 and roof lamp module terminal #7A. Check for a short-circuit to supply voltage.
Check the cable between control module terminal #4 and roof lamp module terminal #8A. Check for a short-circuit to supply voltage.
Replace the cable if a fault is found.

Other information:
- For further information about signals and other values, see Signal specification Signal Specification, Upper Electronic Module (UEM)
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- To access the roof lamp module switches, see Replacing interior lighting Service and Repair
- To access the connector for the upper electronic module (UEM), see Upper electronic module (UEM) rear view / door mirror, replacing Service and Repair
- With the ignition on and when the function is not activated, the voltage between terminals #7A and #8A and ground should be 0 V
- Checking wiring and terminals Checking Wiring And Terminals.









Was a fault detected?

Yes - Verification

No - Replacing the component

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Replacing the component
Remove the housing with the buttons.
Press directly on the switch for the light button.
If the switch works, replace the lamp housing.
If the switch still does not operate, replace the printed circuit board with switches.

Other information:
- To access the interior lighting, see Replacing interior lighting Service and Repair.


Continue - Verification

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Verification




Verification

Verification

Hint: After the repair it is necessary to check that the fault has been rectified.








- Ignition off.
- Connect the connectors, install the components, etc.
- Ignition on.
Press the lamp switch and check that the lamps come on and that the switch does not stick.

Does it work?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - Fault Found

VERIFICATION FAILED - Fault-tracing information

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Fault-tracing information




Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - FAULT-TRACING FAILED

No - Attempt New Test

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Attempt New Test - Checking for permanent or intermittent faults

FAULT-TRACING FAILED - No Fault Found

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Fault-tracing information




Information

Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
It is possible to view the information again, or leave fault-tracing for this diagnostic trouble code (DTC).

Do you want to view the information again?

Yes - Attempt New Test

No - Fault Found

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FAULT FOUND - Fault Found

Attempt New Test - Checking for permanent or intermittent faults

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Intermittent fault
Check the control module and roof lamp module connectors. Check for contact resistance and oxidation. Check for loose connections.
Check the cable between control module terminal #16 and roof lamp module terminal #7A. Check for an intermittent short-circuit to supply voltage. Check for an intermittent open-circuit.
Check the cable between control module terminal #4 and roof lamp module terminal #8A. Check for an intermittent short-circuit to supply voltage. Check for an intermittent open-circuit.
Check the roof lamp module housing.
Check the roof lamp module switches.

Other information:
- For further information about signals and other values, see Signal specification Signal Specification, Upper Electronic Module (UEM)
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- To access the roof lamp module switches, see Replacing interior lighting Service and Repair
- To access the connector for the upper electronic module (UEM), see Upper electronic module (UEM) rear view / door mirror, replacing Service and Repair
- With the ignition on and when the function is not activated, the voltage between terminals #7A and #8A and ground should be 0 V
- Checking wiring and terminals Checking Wiring And Terminals.










Continue - Fault-tracing information

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