Component Tests and General Diagnostics

Checking front fog lamps

Fault-tracing information
Front fog lamps are supplied with power via a relay positioned in the integrated relay/fusebox in the engine compartment.
The front fog lamps do not work due to:
- Blown bulb
- Burnt out fuse
- Damaged relay
- Defective switch
- Open-circuit in the signal cable.
For information about fuse numbers and the number on the terminal pins, see the Wiring diagram.

Continue - Checking components

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Checking components
Check that the following components are intact:
- Front fog lamp bulbs
- Front fog lamp fuse
- Front fog lamp switch.
For information about fuse numbers and the number on the terminal pins, see the Wiring diagram.

Checking the relay
Check that the fog lamp relay is correctly installed.
Also check the relay terminal, in particular terminal #5. Check for a short-circuit to ground.
Check the function of the front fog lamp relay. Activate and deactivate the relay a number of times. The relay is functioning if there is a clicking sound when the relay is activated and deactivated.
Click the VCT2000 symbol to activate and deactivate the relay.
Remedy as necessary





Was a fault detected?

Yes - Verification

No - Checking the wiring

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Checking the wiring
Check the signal cable between the central electronic module (CEM) and the light switch module (LSM). Check for an open-circuit. Check for a short-circuit to supply voltage.
Take readings between:
- Central electronic module (CEM) terminal #B23 (#23) and light switch module (LSM) connector terminal #3.
Check the signal cable between central electronic module (CEM) terminal and the fog lamp relay. Check for an open-circuit. Check for a short-circuit to supply voltage.
Take readings between:
- Central electronic module (CEM) terminal #G9 (#9) and fog lamp relay connector terminal #2.
Check the signal cable between the fog lamp relay and the right and left-hand fog lamp bulbs. Check for an open-circuit. Check for a short-circuit to ground.
Take readings between:
- The fog lamp relay connector terminal #5 and the right and left-hand fog lamp bulb connector terminal #1.
Remedy as necessary

Other information
- Connecting the breakout box Connecting The Breakout Box, Central Electronic Module (CEM)
- Checking wiring and terminals Checking Wiring And Terminals

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 front fog lamp.
Check that the function is OK.

Is the function OK?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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Fault-tracing information

FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Fault-tracing information

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