How to Repair the Dimmer Switch on a Chevy Truckby Jack Hathcoat
Older models of Chevy trucks use a dimmer switch that is repairable. New styles are not repairable, and replacement is the only option. General Motors produced the adjustable switch for decades, and it is located on top of the steering column. An activator rod extends the length of the column, starting at the turn-signal, dimmer-switch lever and ending at the switch.
Remove the lower trim plate, just under the steering column, with a Phillips screwdriver. Shine a flashlight under the dashboard, and spot four bolts that attach the column to the steering column mounting bracket. Remove the bolts, and lower the column, until the steering wheel rests on the driver's seat.
Operate the dimmer switch lever several times, and shine the flashlight along the top edge of the column. A slender rod should move, as the lever is retracted and released. The rod is routed into the dimmer switch. Verify that two wires are plugged into the switch, which is a round, metal canister.
Use a wrench, and loosen the two mounting bolts that hold the switch in place. It mounts in place with the ignition switch, so do not completely remove the screws. Lightly pull the switch forward, while operating the switch handle. Stop when the switch no longer clicks on and off. It is too far forward, if it does not have a distinctive click sound, as it operates. Adjust the switch at the most forward limit.
Turn the headlights on, and operate the switch. Verify the headlights change from bright to dim. If the switch fails to work after this repair, replace it. Reinstall the steering column, and replace the under-column trim panel.
- "Truck and Van Repair Manual", Chiltons: 1990
- By moving the switch forward, the contacts now press more firmly together. If there is light oxidation on the contacts, enough to prevent the switch from working, this repair procedure improves the connection, and there is a good chance the switch will work.
Things You'll Need
- 3/8-inch socket set
- Wrench set
Jack Hathcoat has been a technical writer since 1974. His work includes instruction manuals, lesson plans, technical brochures and service bulletins for the U.S. military, aerospace industries and research companies. Hathcoat is an accredited technical instructor through Kent State University and certified in automotive service excellence.