Shawn MacAnanny
Full Access Member
Because of some alternator wiring issues I saw, I assumed the alternator was bad on the 1990 truck I purchased and that's why the light was on. Im finally getting around to working on it now and alternator is fine putting our 13.8 to 14.0 at idle. The oil pressure gauge works, the temperature gauge works. Oil level is fine. What else could cause the light to illuminate? Anything to do with the fuel filter or is the and engine over temp coolant temp probe that could be bad?