Automatic Dimming Inside Mirror Test/Replacement
Automatic Dimming Inside Mirror Test/ReplacementWithout OnStar System:
1. Remove the front ceiling light.
2. Disconnect the 3P connector (A) from the automatic inside dimming mirror (B).
3. Check for continuity between No. 3 terminal and body ground.
- If there is continuity, go to step 4.
- If there is no continuity, check for:
- an open in the wire.
- poor ground(G581).
4. Check for voltage between No.1 terminal and body ground with the ignition switch ON (II).
- If there is battery voltage, go to step 5.
- If there is no voltage, check for:
- blown No. 9 (7.5 A) fuse in the driver's under-dash fuse/relay box.
- an open in the wire.
5. Check for voltage between No. 2 terminal and body ground with the ignition switch ON (II) and Transmission range switch in [R].
- If there is battery voltage, replace the mirror assembly.
- If there in no voltage, check for:
- an open in the wire.
- faulty reverse relay.
- faulty Transmission range switch.
OnStar System:
NOTE: Before testing, check the NO. 13 (7.5 A) fuse. NO. 7,10,11,13,14, and 15 terminals are OnStar switches microphone power, ground and signal lines.
1. Disconnect the 16P connector from the mirror.
2. Check for voltage between the NO. 12 terminal and body ground with the ignition switch ON (II).
- If there is battery voltage, go to step 3.
- If there is no voltage, check for:
- an open in the wire.
3. Check for voltage between the NO. 16 terminal and body ground with the ignition switch ON (II) and A/T gear position in [R].
- If there is battery voltage, replace the mirror by removing torx screw.
- If there is no voltage, check for:
- an open in the wire, or
- faulty reverse relay, or
- faulty transmission range switch.