Automatic Dimming Inside Mirror (4-cyl) Acura TSX II

Scheme 53

System Description

The automatic dimming inside mirror has a front-facing lux level sensor (A), rear-facing lux level sensors (B), and a control unit. The control unit receives signals from each sensor. Based on the difference between the two lux levels (the light outside the vehicle and the light from the headlights of the other vehicle, etc.), the control unit controls the electro-chromic gel to reduce the glare. This dimming function is canceled when the transmission is in reverse, or when the automatic dimming off button (C) is turned OFF.

Scheme 54

Scheme 55

1. Check for obstructions (parking stickers, labels, etc.) over the front-facing lux level sensor (A).
2. Remove the cover (B), then disconnect automatic dimming inside mirror 7P connector (C).
3. Turn the ignition switch to ON (II).
4. Measure the voltage between terminal No. 2 and body ground. If there is less than 0.2 V, go to step 5. If there is more than 0.2 V, check for: Poor ground (G501). An open or high resistance in the wire.
5. Measure the voltage between terminal No. 1 and body ground. If there is battery voltage, go to step 6. If there is no voltage, check for: Blown No. 5 (7.5 A) fuse in the driver's under-dash fuse/relay box. An open or high resistance in the wire.
6. Measure the voltage between terminal No. 3 and body ground with the shift lever in R (reverse) position. If there is battery voltage, replace the mirror assembly. If there is no voltage, check for: Faulty driver's under-dash fuse/relay box. Faulty transmission range switch (A/T). Faulty back-up light switch (M/T). An open or high resistance in the wire.