Component Tests and General Diagnostics

The ambient and glare sensors and associated circuitry, the sensitivity control and reverse over-ride circuitry are all contained within the mirror unit. Therefore only the inputs to the mirror unit can be interrogated, and if correct, the mirror unit is defaulted.
- Measure voltage between mirror pin 1 and ground. Value should indicate battery voltage, i.e. 12 V nominal.
- If an abnormally low or zero voltage is recorded, check fuse F14, RH 'A' post fuse-box, check wiring harness continuity between mirror unit pin 1 and fuse F14.
- Check the ground connection at the mirror unit pin 3.


NOTE: The mirror unit shares a common ground with the roof console and the sliding roof, therefore a fault within the ground would effect all three systems.


- Check for 12 V at mirror unit pin 2 when reverse gear selected, ignition ON; falling to 0 V on deselection of reverse.

Electrochromatic Rear View Mirror Schematic, Fig.1:

1. Mirror assembly
2. RH A post fuse-box
3. Rear LCM
4. RH reverse lamp
5. Roof console (GND)
6. Sliding roof CM (GND)