Jim Grant's Tech Tips
‘89 Pontiac Grand Am, Gauge Lights
Q: I'm having a really baffling problem with my ’89 Pontiac Grand Am!! My panellights don’t work in my car, so night-time driving is a pain because Ican’tsee how fast I’m going or how much gas I have, without turning on my dome lights.Some lights inside my panel work, such as the seatbelt sign, the oil sign, the "CheckEngine" light works, but when I have my headlights on, my speedometer and odometer(as well as others) aren't lit up and I can't see a thing. What could cause thisproblem?
A: On your headlight switch assembly there is a dimmer switch for the dash lights, it is the same one you’ve been using to turn on your interior lights to see the gauges. This switch feeds a component called a dimmer module that controls the flow of electricity to the light on the instrument panel. In between the module and the bulbs for the instrument panel is a 5 amp fuse marked “inst lps”. With the lights on check for power to this fuse. It is likely that you’ve already checked the fuse’s condition. If there is no power to the fuse than you know that the module or the dimmer switch is the cause. With the headlight switch assembly removed check the brown wire in the “C” location of the connector the to headlight switch assembly with the lights on. If there is power move the dimmer control to see if there is a change in voltage. If there is you likely need a dimmer module. If not then the dimmer control needs replacing.