Checking The Instrument Lighting

Checking the instrument lighting

Checking the signal from the rheostat




- Ignition on.
Move the lighting switch to position 1.
Turn the rheostat. Read off the signal from the rheostat. The value must vary between 0 and 60°.





Does the value vary between 0 and 60°?

Yes - Checking wiring and components

No - Checking wiring and components

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Checking wiring and components




- Ignition off.
Check that fuse 18 the integrated relay / fusebox in the engine compartment is intact.
Check the cable between control module connector F #11 (#B11) and fuse 18 and the cable between control module connector P #6 (#B26) and lighting switch #10 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault , contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the following cables. Check the cable between control module connector P #5 (#B25) and left and right parking lamps connector #1. Check the cable between fog lamp switch connector #2 and control module connector P #8 (#B28). Check these cables for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Try a new switch if no fault is found in the cables.
Remedy as necessary.

Other information
- To connect the breakout box, see Connecting the breakout box Connecting The Breakout Box. Central Electronic Module (CEM).
- For information about signals, see Signal specification Signal Description. Central Electronic Module (CEM).
- To access / replace the switch see Replacing rocker switch Replacing Rocker Switch.













Continue - Verification

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Checking wiring and components




- Ignition off.
Check that the bulbs for the instrument lighting are intact.
Check the following cables. Check the cable between control module connector P #14 (#B34) and combined instrument panel connector #A9. Check the cable between combined instrument panel connector #A13 and the ground terminal. Check these cables for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Remedy as necessary.

Other information
- To connect the breakout box, see Connecting the breakout box Connecting The Breakout Box. Central Electronic Module (CEM).
- For information about signals, see Signal specification Signal Description. Central Electronic Module (CEM).









Continue - Verification

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off.
- Reinstall the connectors, components etc.
- Ignition on.
Activate the instrument lighting at 42% and 100% strength.
Check that the luminance of the instrument lighting changes.





Is the instrument lighting OK?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFICATION FAILED - Fault-tracing information

VERIFIED - FAULT FOUND

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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 - Exit fault-tracing

No - Attempt New Test

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Attempt New Test - Checking the signal from the rheostat

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