Instrument Cluster Dimmer Switch Control Unit Input
NOTE:
Before testing instrument dimmer switch control functions, ensure multiplex control system is operating properly. See appropriate
MULTIPLEX CONTROL SYSTEMS article.
- Remove driver's underdash fuse/relay box. See DRIVER'S UNDERDASH FUSE/RELAY BOX under REMOVAL & INSTALLATION. Remove driver's multiplex control unit from driver's underdash fuse/relay box. Disconnect driver's multiplex control unit harness connector. Also disconnect driver's underdash fuse/relay box 18-pin connector "J" and 20-pin connector "M". See Fig 1 . Inspect connectors and terminals. Check for bent, loose or corroded terminals. Perform driver's multiplex control unit input test "A". See Fig 2 . Repair as necessary and recheck system operation. If driver's multiplex control unit inputs are okay, go to next step.
- Reconnect driver's multiplex control unit to underdash fuse/relay box. Perform input test "B" as specified, on back side of driver's fuse/relay box (backprobe). Repair as necessary.