My digital cluster in my 94 caprice works when the headlight switch is off but when i turn the headlight switch on it goes out anybody ever had that problem or is it my wiring going bad?
I'm going from fuzzy memory here, so double check what I'm saying. There is a remote dimmer module somewhere under the dash, AC Delco p/n D1509B. It is a transistor circuit that controls dash illumination when the lights are on. I believe (again, double check me here) that when it fails the dash lights work only when the headlight switch is off. The factory service manual has the complete troubleshooting sequence I think. Note that this module is NOT the dimmer switch-- it is separate. Rockauto has them for about $30. They're used on a bunch of GM vehicles from mid-80s on up, so you can probably find one in the boneyard if you want a cheap one as a "try-and-see" part.