it is a 48 gmc 1/2 ton, it is all new wire, all new switches,the only thing I have hooked up is the headlights, parking lights, brakes lights and directional...my ground in coming off the engine then into cab, at a junction box, then separate ground wires to front and back, all lights front and back work great, I have no lights for the gauges, only wire hook under dash is the high beam indicator, from dimmer switch, have high beam wire to headlights, same with low beam, high beam indicator wire hook to high beam bulb, maybe bad dimmer switch, also tried hooking wire from high beam connection to high beam indicator on dash, still bulb works same way.
