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Test F: Automatic Dimming Function Inoperative

NOTE: Inside automatic dimming mirror may also be referred to as electronic day/night mirror.
  1. Place transmission in Park. Turn ignition switch to RUN position. Cover light sensor on back side of inside mirror. Shine bright light into front of inside mirror. If inside mirror does not darken, go to next step. If inside mirror darkens and driver's exterior mirror does not darken, go to step  7 . If both mirrors darken, system is operating properly at this time.
  2. Turn ignition switch to LOCK position. Disconnect inside mirror harness connector C902. Connector is located at center of windshield header on mirror. Turn ignition switch to RUN position. Measure voltage between ground and inside mirror harness connector C902 terminal No. 7 (Dark Blue/Light Green wire). See Fig 1 . If battery voltage does not exist, go to next step. If battery voltage exists, go to step  5 .
    Fig 1: Identifying Inside Mirror Harness Connector C902 Terminals
    G98D01586Courtesy of FORD MOTOR CO.
  3. Turn ignition switch to LOCK position. Remove central junction box fuse No. 18 (7.5-amp). If fuse is blown, go to next step. If fuse is okay, repair open in Dark Blue/Light Green wire between fuse No. 7 and inside mirror.
  4. Ensure fuse No. 18 is still removed. Measure resistance between ground and inside mirror harness connector C902 terminal No. 7 (Dark Blue/Light Green wire). If resistance is 10 k/ohms or less, repair short to ground in Dark Blue/Light Green wire between fuse No. 7 and inside mirror. If resistance is 10 k/ohms or more, replace inside mirror. Retest system for normal operation.
  5. Measure resistance between ground and inside mirror harness connector C902 terminal No. 6 (Black wire). If resistance is 5 ohms or less, go to next step. If resistance is 5 ohms or more, repair open in Black wire between ground and inside mirror. Ground point is located behind driver's kick panel, near door frame.
  6. Turn ignition switch to RUN position. Place transmission in Reverse. Measure voltage between ground and inside mirror harness connector C902 terminal No. 5 (Black/Pink wire). If battery voltage exists, replace inside mirror. If battery voltage does not exist, repair open in Black/Pink wire between digital transmission range sensor and inside mirror.
  7. Turn ignition switch to LOCK position. Disconnect inside mirror harness connector C902. Connect a D-size battery (1.5 volts or less), positive to terminal No. 4 (Violet wire) and negative to terminal No. 3 (Light Blue/White wire) to inside mirror harness connector C902. See Fig 1 . If driver's exterior mirror does not darken disconnect battery, and go to next step. If driver's exterior mirror darkens, replace inside mirror.
  8. Turn ignition switch to LOCK position. Disconnect driver's exterior mirror harness connector C508. Connect inside mirror harness connector C902. Measure voltage between ground and driver's exterior mirror harness connector C508 terminal No. 9 (Light Blue/White wire). See Figure . If voltage exists, go to next step. If no voltage exists, go to step  10 .
  9. Disconnect inside mirror harness connector C902. Measure voltage between ground and driver's exterior mirror harness connector C508 terminal No. 9 (Light Blue/White wire). If voltage exists, repair short to voltage in Light Blue/White wire between inside mirror and driver's exterior mirror. If no voltage exists, replace inside mirror.
  10. Measure voltage between ground and driver's exterior mirror harness connector C508 terminal No. 10 (Violet wire). If voltage exists, go to next step. If no voltage exists, go to step  12 .
  11. Disconnect inside mirror harness connector C902. Measure voltage between ground and driver's exterior mirror harness connector C508 terminal No. 10 (Violet wire). If voltage exists, repair short to voltage in Violet wire between inside mirror and driver's exterior mirror. If no voltage exists, replace inside mirror.
  12. Measure resistance between ground and driver's exterior mirror harness connector C508 terminal No. 9 (Light Blue/White wire). If resistance is 10 k/ohms or less, go to next step. If resistance is 10 k/ohms or more, go to step  14 .
  13. Disconnect inside mirror harness connector C902. Measure resistance between ground and driver's exterior mirror harness connector C508 terminal No. 9 (Light Blue/White wire). If resistance is 10 k/ohms or less, repair short to ground in Light Blue/White wire between inside mirror and driver's exterior mirror. If resistance is 10 k/ohms or more, replace inside mirror.
  14. Measure resistance between ground and driver's exterior mirror harness connector C508 terminal No. 10 (Violet wire). If resistance is 10 k/ohms or less, go to next step. If resistance is 10 k/ohms or more, go to step  16 .
  15. Disconnect inside mirror harness connector C902. Measure resistance between ground and driver's exterior mirror harness connector C508 terminal No. 10 (Violet wire). If resistance is 10 k/ohms or less, repair short to ground in Violet wire between inside mirror and driver's exterior mirror. If resistance is 10 k/ohms or more, replace inside mirror.
  16. Disconnect inside mirror harness connector C902. Measure resistance in Light Blue/White wire between terminal No. 3 at inside mirror harness connector C902 and terminal No. 9 at driver's exterior mirror harness connector C508. If resistance is 5 ohms or less, go to next step. If resistance is 5 ohms or more, repair open in Light Blue/White wire between inside mirror and driver's exterior mirror.
  17. Measure resistance in Violet wire between terminal No. 4 at inside mirror harness connector C902 and terminal No. 10 at driver's exterior mirror harness connector C508. See Figure and Fig 1 . If resistance is 5 ohms or less, replace driver's exterior mirror. If resistance is 5 ohms or more, repair open in Violet wire between inside mirror and driver's exterior mirror.
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