Ok here's my prob, I got a 93 f250 7.3 idi standard cab, ok when I turn on my running lights the lights work fine but when I turn on my head lights the driver side head light does not come on n the running light turns off but the others stay on. Now I checked my fuses n bulbs, they r all good so pulled the dash apart to check the dimmer switch it had one wire that melted the connecter around it from a loose connection. I fixed that n it still don't work. I checked the turn singal switch n cleaned it now my radio button lights don't light up n the display flashes when I use the turn singal. WTF!!!! What could be doing this. Please help

 

Grounding problems. Follow the ground wires for the driver's side headlight and the driver's side turnsignal. It should be bolted somewhere on the radiator support I believe, but not sure.

Make sure you have a ground wire going from the engine block (usually one of the bellhousing bolts that holds the transmission) to the firewall sheetmetal. Make sure you also have a wire from the battery negative to the radiator support. Sometimes it's easier to add these ground wires rather than trying to find the factory ones.