Acura 3.5 RL Manual page 1157

Test/Replacement ('02-04 Model USA)
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
3. Check for voltage between the No. 16 terminal and
Wire side of
female terminals
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, or
— poor ground (G401, G402).
body ground with the ignition switch ON (II) and
A/T gear position in
• 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, or
— faulty diode.