Instrument Lighting

Condition:

VDO Instrument Cluster W/Turbo:

- All combined instrument panel gauges working.
- Lighting in controls working.

Possible Source:
- Open-circuit in lighting ground.
- Defective rheostat.
- Defective bulbs.

Start fault-tracing with "Checking Instrument Lighting", below.

Checking Instrument Lighting:

1) Checking Indicator Lamps:

Ignition On:

- Ignition on.





- Switch on headlamps.
- Set the instrument lighting rheostat to maximum.
- Check whether the fog tail lamp, high beam and turn indicator flasher indicator lamps light.
- Do the indicator lamps light?

Yes: Go to step 2, below.
No: Go to step 3, below.

2) Checking for an Open-Circuit:





- Check cable between combined instrument panel # A17 and ground terminal 31/50 for an open-circuit. Checking Cables and Terminals
- Then continue with step 6, below.

3) Checking Voltage to Bulbs:
- Ignition off.





- Connect breakout box and check ground terminals. Connecting Test (Breakout) Box
- Connect combined instrument panel.

Ignition On:

- Ignition on.
- Switch on headlamps.
- Set the instrument lighting rheostat to maximum.





- Use a voltmeter to measure between # 10 (# A10) and # 17 (# A17) on the breakout box.
- The voltmeter should read approx. battery voltage.

If reading is OK go to step 4, below.
If reading is incorrect go to step 5, below.

4) Replacing Component:
- Try new instrument lighting bulbs. Instrument Panel Bulb
- Then continue with step 6, below.

5) Checking for an Open-Circuit:





- Check cable between combined instrument panel # A10 and junction point 23/300 for an open-circuit. Checking Cables and Terminals
- For further information about the circuit, see Wiring Diagram.
- Then continue with step 6, below.

6) Verification:

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

- Ignition off.

Connect Connector:

- Reconnect connectors, reinstall components.





- Connect combined instrument panel.

Ignition On:

- Ignition on.





- Switch on headlamps.
- Set the instrument lighting rheostat to maximum.
- Does the instrument lighting light?

Yes: Fault is corrected.
No: The verification result shows that the fault persists. Do you want to quit fault-tracing?
Yes: Fault is not corrected
No: Start over at step 1, above.