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.

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.

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

Attempt New Test - Fault-tracing information

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