Auto Dimming Mirror Chevrolet Impala VIII

DESCRIPTION

Electrochromatic day/night rearview mirror automatically changes reflectance to reduce glare from headlights. At night, as glare of headlights from behind increases, mirror will gradually become darker to absorb glare. During daylight, or when gearshift lever is in Reverse, mirror will be clear and fully reflective. On some models, driver's side outside mirror will also be an electrochromatic day/night mirror that is controlled by inside mirror.

OPERATION

Day/night mirror(s) use a thin layer of electrochromatic material between 2 plates of conductive glass. Two photocell sensors signal levels of light to a logic circuit. A forward-facing photocell sensor measures ambient light levels. A rear-facing photocell sensor measures glare from approaching vehicle headlights. When logic circuit senses more light from the headlight sensor than the ambient light sensor, the electrochromatic drive circuit applies voltage to mirror(s). Approximately 1.15 volts is applied to mirror(s) when a large amount of glare is present, causing mirror(s) to darken. Voltage will be reduced to 0.01 volt when both photocells indicate the same light level.

When gearshift lever is shifted into Reverse, battery voltage is applied to mirror reset terminal. Mirror will gradually change to a clear state for better vision when backing up.

AUTOMATIC DAY/NIGHT MIRROR SYSTEM CHECK

1. Turn ignition switch to RUN position. Move gearshift lever into Park. Move mirror switch to MAXIMUM, ON or MIRROR position, if necessary. Cover ambient light sensor (windshield side of mirror) with a dark cloth. Shine light on headlight sensor (on mirror side). Mirror should gradually darken.
2. Move gearshift lever into Reverse. Mirror should gradually lighten to a clear state. Move gearshift lever into Park. Mirror should gradually darken. Remove cloth and light. Mirror should gradually lighten to a clear state. If mirror does not operate as specified, go to «SYSTEM TESTS»(/chevrolet/impala/viii-1999-2006/remont/mirrors/#auto-dimming-mirror__system-tests) .

WIRING HARNESS & ELECTRICAL CONNECTORS

Many intermittent open or shorted circuits come and go with harness or connector movement caused by following conditions

1. Vibration
2. Engine Torque
3. Bumps Or Rough Pavement

Test for intermittents by moving related connectors and wiring while monitoring appropriate scan tool data. With engine running, move related connectors and wiring while monitoring engine operation. Verify if harness or connector movement affects scan tool data display, component or system operation or engine operation. Repair condition as necessary.

Intermittents caused by electrical connectors are usually caused by one or more of following conditions

1. Poor Electrical Connections
2. Terminal Tension
3. Wiring Problems

Check for poor mating of connector halves, terminals backed out or not fully seated in connector body, improperly formed or damaged terminals or poor terminal tension. Also check for poor terminal-to-wire connections including terminals crimped over insulation, swollen and stiff sections of wire in suspect circuits, wires that are broken inside insulation, pinched, cut or rubbed through wiring or wiring that is in contact with hot exhaust components. Repair condition as necessary.

CONTROL MODULE, & COMPONENT POWER & GROUNDS

Many vehicles have multiple circuits supplying power to control modules. Other components may have separate power circuits that may also need to be tested. Check connections at module or component connectors, fuses, and any intermediate connections between power source and module or component. Ensure that circuit can carry current necessary to operate component. Test all control module ground and system ground circuits. Control module may have multiple ground circuits. Other components may have separate grounds that may also need to be tested. Check grounds for clean and tight connections at ground connection. Check the connections at the component and in splice packs, where applicable. Ensure that circuit can carry current necessary to operate component.

TEMPERATURE SENSITIVITY

An intermittent condition may occur when a component or connection reaches normal operating temperature. Condition may occur only when component or connection is cold, or hot. Use freeze frame and failure records, scan tool snapshot or vehicle data recorder to help diagnose this type of intermittent. If intermittent is related to heat, check for high ambient temperatures, underhood or engine generated heat, circuit generated heat due to a poor connection, or high electrical load. If intermittent is related to cold, check for low ambient temperatures or water intrusion.

ELECTROMAGNETIC INTERFERENCE & ELECTRICAL NOISE

Some electrical components or circuits are sensitive to Electromagnetic Interference (EMI) or other types of electrical noise. Check for misrouted wiring that is too close to high voltage or high current devices. Check for wires that are too close to secondary ignition components, electrical motors or the generator. Check for non-factory or aftermarket add-on accessories such as lights, 2-way radios, amplifiers, electric motors, remote starters, alarm systems, or cell phones. Test for open diode across AC compressor. Some relays may contain a clamping diode. Check that generator is operating properly.

SYSTEM TESTS

Note. To identify connectors, terminals and wire colors, see WIRING DIAGRAMS .

INSIDE AUTOMATIC DAY/NIGHT MIRROR INOPERATIVE

1. Review operation of automatic day/night mirror. If automatic day/night mirror does not operate properly, go to next step.
2. Turn ignition switch to ON position. Turn on automatic day/night mirror feature of inside rear view. Cover sensor on inside rear view mirror back (side facing windshield). Shine bright light into sensor on inside rear view mirror face. If inside rear view mirror does not darken, go to next step. If inside rear view mirror darkens, problem is intermittent. See «DIAGNOSING INTERMITTENTS»(/chevrolet/impala/viii-1999-2006/remont/mirrors/#auto-dimming-mirror).
3. Turn ignition switch to OFF position. Disconnect automatic inside rear view mirror harness connector. Using DVOM, measure resistance at harness connector terminal No. 8 between automatic inside rear view mirror ground circuit (Black wire) and good ground. (Scheme 1) If resistance of ground circuit is 3 ohms, go to next step. If resistance of ground circuit is not 3 ohms, go to step 10.
4. Turn ignition switch to ON position, engine off. Measure voltage between ignition 3 voltage circuit (Brown wire) terminal No. 13 and ground circuit (Black wire) terminal No. 8 of automatic inside rear view mirror. (Scheme 1) If battery voltage is present, go to next step. If battery voltage is not present, go to step 9.
5. With transmission in Park, measure voltage between back-up light supply voltage circuit (Light Green wire) terminal No. 9 and ground circuit (Black wire) terminal No. 8 of automatic inside rear view mirror. (Scheme 1) If measured voltage is less than.5 volt go to next step. If measured voltage is not less than.5 volt, repair back-up lights always on condition. See BACK-UP LIGHTS in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
6. With transmission in reverse, measure voltage between back-up light supply voltage circuit (Light Green wire) terminal No. 9 and ground circuit (Black wire) terminal No. 8 of automatic inside rear view mirror. (Scheme 1) If battery voltage is not present, go to next step. If battery voltage is present, go to step 8.
7. Check automatic inside rear view mirror back-up light voltage supply circuit (Light Green wire) for open or high resistance. If open circuit or high resistance is present, repair as necessary. After repair, go to step 12. If open circuit or high resist is not present, repair inoperative back-up lights condition. See BACK-UP LIGHTS in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
8. Check for poor connections at automatic inside rear view mirror harness connector. See «WIRING DIAGRAMS»(/chevrolet/impala/viii-1999-2006/remont/mirrors/#auto-dimming-mirror). If poor connection(s) is present, repair as necessary. After repair go to step 12. If poor connection(s) is not present, go to step 11.
9. Repair open or short to ground in automatic inside rear view mirror ignition 3 voltage circuit. See «WIRING DIAGRAMS»(/chevrolet/impala/viii-1999-2006/remont/mirrors/#auto-dimming-mirror). After repair go to step 12.
10. Repair open or high resistance in automatic inside rear view mirror ground circuit. See «WIRING DIAGRAMS»(/chevrolet/impala/viii-1999-2006/remont/mirrors/#auto-dimming-mirror). After repair, go to step 12.
11. Replace automatic inside rear view mirror. After repair, go to next step.
12. Operate automatic inside rear view mirror system. If system operates normally, system is okay. If automatic inside rear view mirror system does not operate properly, go to step 2.

Scheme 1

REMOVAL & INSTALLATION

Note. Electrochromatic mirror cannot be repaired, and must be replaced as an assembly. DO NOT use ammonia-based cleansers on electrochromatic day/night mirrors. Spraying cleansers directly on mirrors is not recommended.

Remove wiring harness cover from lighted rearview mirror, if equipped. Using small flat-blade tool, remove rearview mirror from support. Disconnect electrical connector, if equipped. To install, reverse removal procedure.

For vehicles with driver's side outside electrochromatic mirror, see POWER MIRROR ASSEMBLY under REMOVAL & INSTALLATION in POWER MIRRORS - IMPALA & MONTE CARLO article.

IMPALA

1. For 2001 wiring, see «POWER MIRRORS»(ref-132285-S19002978372002121100000) in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
2. For 2002 wiring, see «POWER MIRRORS»(ref-151178-S23834680242002121200000) in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

MONTE CARLO

1. For 2001 wiring, see «POWER MIRRORS»(ref-132289-S07263970352002121100000) in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
2. For 2002 wiring, see «POWER MIRRORS»(ref-151180-S10214888022002121200000) in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

See also:
• POWER MIRROR ASSEMBLY
• SYSTEM TESTS
• WIRING DIAGRAMS