Dimmer Switch Circuit
WARNING: This page is about a different car, the 1993 Honda Prelude. However, it is still accessible from the selected car via links, so may be relevant.
- Turn ignition off. Carefully pry dimmer switch from dashboard. Dimmer switch is removed with 2 other switches in a pod. Unplug dimmer switch 6-pin connector.
- Using a DVOM, measure resistance of dimmer switch terminals "C" and "E". See Fig 1 . Resistance should be 8000-10,000 ohms. Resistance will vary slightly with temperature. If resistance is as specified, go to next step. If resistance is not as specified, replace dimmer switch.
- Using a DVOM, measure resistance of dimmer switch terminals "D" and "E". See Fig 1 . Resistance should vary between zero and 10,000 ohms when dimmer switch dial is rotated. Resistance will vary slightly with temperature. If resistance is as specified, go to next step. If resistance is not as specified, replace dimmer switch.
- Using a DVOM, check for continuity between dimmer switch terminals "B" and "F". See Fig 1 . If continuity exists, go to next step. If no continuity exists, replace dimmer switch.
- Rotate dimmer switch past its dimmest setting until a "click" is heard. Using a DVOM, check for continuity between dimmer switch terminals "B" and "F". See Fig 1 . If no continuity exists, go to next step. If continuity exists, replace dimmer switch.
- Remove 4 screws from sub-gauge assembly located in center of dashboard. Pull out sub-gauge assembly far enough to unplug electrical connectors. Remove sub-gauge assembly.
- Access dashlight brightness control unit located behind sub-gauge assembly. Unplug dashlight brightness control unit 6-pin connector. See Fig 1 . With headlight switch on or off, use a DVOM to check for continuity between 6-pin connector Black wire and ground. If continuity exists, go to next step. If no continuity exists, repair open Black wire or poor ground connection G401, located under right side of dashboard near base of windshield. Also check ground connection G402, located on left side of left side rail on center console.
- With headlight switch on, use a DVOM to check for battery voltage between 6-pin connector Red/Black wire and ground. If battery voltage exists, go to next step. If battery voltage does not exist, replace blown underhood fuse No. 42 (20-amp), faulty headlight switch or repair open circuit in Red/Black wire.
- With headlight switch on, use a jumper wire to ground 6-pin connector Red wire. If dashlights come on (full bright), go to next step. If dashlights do not come on, repair open circuit in Red/Black wire or Red wire for 6-pin connector.
- Using a DVOM, measure resistance between 6-pin connector Red/Green wire and Red/White wire. Resistance should be 8000-12,000 ohms at all times when dimmer switch dial is rotated. Resistance will vary slightly with temperature. If resistance is as specified, go to next step. If resistance is not as specified, repair open circuit in Red/Green wire or Red/White wire or replace faulty dashlight brightness control unit.
- Using a DVOM, measure resistance between 6-pin connector Red/Blue wire and Red/White wire. Resistance should vary between zero and 10,000 ohms when dimmer switch dial is rotated. Resistance will vary slightly with temperature. If resistance is as specified, go to next step. If resistance is not as specified, repair open circuit in Red/Blue wire or Red/White wire or replace faulty dashlight brightness control unit.
- Ensure connection between 6-pin connector and dashlight brightness control unit is okay. See Fig 2 . If connection is okay, replace dashlight brightness control unit with a known good unit and check operation of cruise control indicator light.