Test I: Auto Dimming Does Not Operate Properly
- Turn ignition switch to RUN position. Move shift control selector through all positions. If reverse lights illuminate only while shift control selector is in Reverse, go to next step. If reverse lights illuminate in any gear position, other than Reverse or not at all, repair reverse lights as necessary. See
BACK-UP LIGHTS article.
- Move shift control selector to Park. Using dark tape, cover sensor on rear of mirror (windshield side). Using a flashlight, direct light into interior rear view mirror front sensor (reflective side). Mirror should darken. Move gear shift selector to Reverse. Mirror should undarken. If mirror operates as specified, auto dimming is operating properly at this time. If mirror only darkens, go to next step. If mirror does not undarken when shifted into Reverse, go to step 7
.
- Turn ignition switch to LOCK position. Move shift control selector to Park. Remove and check Central Junction Box (CJB) fuse No. 23 (10-amp). If fuse is okay, go to next step. If fuse is open, replace fuse. Recheck system operation. If fuse opens again, repair short to ground in White/Light Blue wire between CJB and interior rear view mirror. See WIRING DIAGRAMS
. Recheck system operation.
- Disconnect interior rear view mirror 7-pin harness connector C904. Turn ignition switch to RUN position. Measure voltage between ground and interior rear view mirror harness connector C904 terminal No. 7 (White/Light Blue wire). See Fig 1
. If more than 10 volts exists, go to step 6
. If 10 volts or less exists, go to next step.
- Turn ignition switch to LOCK position. Disconnect CJB 34-pin harness connector C243. Measure resistance in White/Light Blue wire between interior rear view mirror harness connector C904 terminal No. 7 and CJB harness connector C243 terminal No. 1. See Fig 1
and Fig 2
. If resistance is less than 5 ohms, replace CJB. Recheck system operation. If resistance is 5 ohms or greater, repair open or high resistance in White/Light Blue wire. See WIRING DIAGRAMS
. Recheck system operation.
- Turn ignition switch to LOCK position. Measure resistance between ground and interior rear view mirror harness connector C904 terminal No. 6 (Black wire). See Fig 1
. If resistance is less than 5 ohms, replace interior rear view mirror. Recheck system operation. If resistance is 5 ohms or greater, repair open or high resistance in Black wire between interior rear view mirror and ground G403. Ground G403 is located near fuel tank.
- Disconnect interior rear view mirror 7-pin harness connector C904. Move shift selector to Reverse. Measure voltage between ground and interior rear view mirror harness connector C904 terminal No. 5 (Black/Pink wire). See Fig 1
. If more than 10 volts exists, replace interior rear view mirror. Recheck system operation. If 10 volts or less exists, repair open in Black/Pink wire between Digital Transmission Range (DTR) sensor and interior rear view mirror. See WIRING DIAGRAMS
. Recheck system operation.
Courtesy of FORD MOTOR CO.
Courtesy of FORD MOTOR CO.