Hi everyone I have a 1981 ford f250 custom camper. There are 3 wires coming from the alternator one is hooked to the starter solenoid one to the voltage regulator I believe but there is a third wire not hooked up which has a plug in end, not sure what to call it but I was wondering where that plug in wire goes I'm thinking a solenoid mounted on the engine or something but not sure. I do know I need to find someone who knows electrical and with it being a camper it has a isolator (not hooked up), an onboard battery charger (no clue).

 

The wire is probably white/black isn't it? If it is, it goes to the electric choke on the carb. Look for a round black piece, there will be a terminal on it on the pass side of the carb. If the carb has been changed, there may not be a place for it anymore.