Hi I was wondering if anyone could help with some trouble I’m having with my 2011 F250 Diesel. I dented the front bumper and bought a new one that came with the fog lights built in. The truck didn’t have a factory switch so I though I would splice them into the right side low beam head light. I tested it and it worked fine. I shut the lights off and put everything back together. When I turned it back on neither the right low beam head light or fog lights worked.. I tested the wires and fuses and can’t find the trouble. Does anyone know if there is a relay or some kind of censor that I might have blown? It’s not in the wiring or bulb because my fisher plow lights on that side don’t work as well.. Any help would be great.. my email is cstrucking@ns.sympatico.ca

 

If you have the owner's manual, check the fuse and relay pages. It should tell you where the fuse and relay for the Right Side low beam headlight is located. There is a good possibility you overloaded that circuit by connecting the fog lights to it. The best way would be to use the headlight low beam supply from either side to energize a separate switch for a relay to feed the fog lights. If you need some assistance I should be able to assist you with the directions to wire them in correctly and safely.

There just may be a position in the relay center just for that purpose. The fuse and relay pages might contain that ifo.

 

Form what I can find out from reading the manual and talking to the dealer is that is only fuses for the low beam head lights and no relays. I have of course swapped out the fuses the fog lights have been disconnected and the headlight wiring harness has be checked and rechecked and still nothing

 

Since this is basic stuff we can check all this with just a test light. Do you have one to use ?
Trace the wires from the plow light on the right side to where it connects to its supply. Does the right side plow lite hi beam work?
Once you have located where the wires for the plow light are connected , one should be for low beam , one for hi beam and possibly a third wire for the ground connection.
You may have to trace the supply wire for the low beam back to where you get voltage/juice. You can also check the fuses this way too. Both sides of the fuse should cause the test lite to lite when connected to a good ground. If you find one fuse that will lite the test lite on one side , but not the other , the fuse is N/G.
The simplest way to hook up the fog lites is to get a standard ISO relay with the 5 prongs on it and it has to have a diode inside it to prevent a voltage spike from being sent into the electrical system. Terms # 85 & 86 are to energize the relay. It is important to connect the ground of the relay coil to the proper terminal of 85 or 86 of the relay coil That relay coil uses very little current and can be tapped into either one of the low beam wires so the relay is activated with a separate switch for the fog lites. The # 30 terminal of the relay is connected with a fuse in the wire to a battery positive connection. This is the supply to the fog lites. Terminal 87A is not used. Terminal # 87 will go to the foglites and supply the voltage to them. You can also place a fuse in that wire to the foglites from terminal 87 and that will protect the wiring in the event a wire gets cut or shorts to ground. Now the foglites will only have juice when the low beam is on and the separate switch for the foglites is turned on. When the foglite switch is turned off the relay opens and the lites won't work. This way you can bypass all the unnecessary wiring trying to use the complicated so called smart junction box in the vehicle.