Test A: Auto Dimming Does Not Operate Properly
WARNING: This page is about a different car, the 2002 Lincoln Blackwood. However, it is still accessible from the selected car via links, so may be relevant.
- 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 EXTERIOR LIGHTS in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
- 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 lighten. If mirror operates as specified, auto dimming is operating properly at this time. If mirror does not darken, go to next step. If mirror does not lighten when shifted into Reverse, go to step 5.
- Disconnect interior rear view mirror 7-pin harness connector C911. Turn ignition switch to RUN position. Measure voltage between ground and interior rear view mirror harness connector C911 terminal No. 7 (White/Light Blue wire). See Fig 1. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 4.
- Turn ignition switch to LOCK position. Measure resistance between ground and interior rear view mirror harness connector C911 terminal No. 6 (Black wire). See Fig 1. If resistance is 5 ohms or less, replace interior rear view mirror. See INTERIOR REAR VIEW MIRROR under REMOVAL & INSTALLATION. Recheck system operation. If resistance is more than 5 ohms, repair open in Black wire between interior rear view mirror and ground. Ground point is located near fuel tank.
- Disconnect interior rear view mirror 7-pin harness connector C911. Move shift selector to Reverse. Measure voltage between ground and interior rear view mirror harness connector C911 terminal No. 5 (Black/Pink wire). See Fig 1. If more than 10 volts exists, replace interior rear view mirror. See INTERIOR REAR VIEW MIRROR under REMOVAL & INSTALLATION. Recheck system operation. If 10 volts or less exists, repair open in Black/Pink wire between digital transmission range sensor and interior rear view mirror. See WIRING DIAGRAMS . Recheck system operation.