Dash Lights Brightness Controller Input Test
- Carefully pry switches from instrument panel. Disconnect controller 3-pin connector. Check for bent, loose or corroded terminals, and repair as necessary. Using DVOM, check for continuity between Black wire terminal and ground. If continuity exists, go to next step. If continuity does not exist, check for open in Black wire. Check for poor ground connections. Repair as necessary.
- Turn combination light switch on. Using DVOM, check for voltage between Red/Black wire terminal and ground. If battery voltage exists, go to next step. If battery voltage does not exist, check for open No. 1 (10-amp) fuse in underdash fuse/relay box. Check for faulty combination light switch. See STEERING COLUMN SWITCHES article. Check for open in Red/Black wire. Repair as necessary.
- Ensure combination light switch is on. Connect a jumper wire between Red wire terminal and ground. If dash lights come on at full brightness, system is operating properly. Replace dash light brightness controller. If dash lights do not come on at full brightness, repair open in Red or Red/Black wire.