E I ect r ica I 
15.4.10 ELECTROCHROMATIC  REAR VIEW MIRROR 
15.4.10.1  Description 
The  function  of the  electrochromatic rearview mirror is  to vary  the reflectivity  of the mirror  glass. The mirror  automati- cally varies  its reflectivity  to accommodate  changes in traffic  and light  conditions  to provide  the driver  with optimized 
forward  and rear  vision. 
The  mirror  contains  an ambient  sensor (forward  facing) and 
a glare sensor  (rearward facing). Sensitivity  control is 
adjustable and at  the lowest  end of sensitivity  control is system off. A reverse over-ride  facility  is incorporated;  when 
reverse gear  is selected,  the mirror  operates in a high  reflective  state. 
15.4.10.2  Test Procedure 
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. 12V nominal. 
. If an abnormally low or zero  voltage is  recorded, check fuse F14, RH 'A' post fuse-box, check  wiring harness  continu- 
. 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 12V  at mirror  unit pin 2 when reverse  gear selected,  ignition ON; falling  to OV on deselection  of reverse. 
/ 
ity  between  mirror unit pin 1 and fuse  F14. 
----- I +12VIGN ! I I I 
I 
L', 
I I 
I ,,J 
F14 1. Mirror  assembly 
2. RH A post  fuse-box 
3. RearLCM 
4. RH reverse  lamp 
5. Roof console (GND) 6. Sliding  roof CM (GND) 
J86-1864 
Fig. 1 Electrochromatic  Rear View  Mirror  Schematic 
Issue 1 August 1994 15.4 - 36 X300 EDM