headlights out

[topgunlandscaping]

om my 93 f-250 if i disconect the western plow i have no headlights or high beams. i have running lights and blinkers and if i plug in the plow all is fine have light hi and low . what do i look for, i cked the bulbs ok, i replaced the relays, no luck????

[MDsnowPRO]

Make sure you flip the trucklights/plow lights switch to truck lights.

[topgunlandscaping]

what switch are you talking about? im not sure i understand. on my old ford i hade a meyers and had a switch that controled the lights on the plow and the truck, but the is a westerm ultra mount the whole thing comes off when i remove the plow

[MDsnowPRO]

See my meyers has that switch thats what i was thinking about..................sorry. My fisher is the way your saying,.

[wyldman]

Well if the plow lamps work fine,then the headlamp\dimmer switch are fine,as well as the wiring and the relays.

I'd say it's probably something on the truck side,like maybe just both bulbs are blown,or the truck side ground is no good.You also could have had a wire or two fall off,or corrode at the relays.

Check for power at the truck headlamps with the headlamps on.If you have power,then it's either a bad bulb,or a bad ground.

If you don't have power at the truck headlamps,then check for power at the relays (orange for low beams,white for high beams).

If you have power,then it's a connection or wiring problem from the relay to the headlamps.No power,and it probably a bad relay contact (internal).

I highly doubt both relays,or both wires would go bad together though,so I'd be looking more at common stuff,like the truck headlamp ground.The plow wiring harness is tapped into only one of the original truck headlamp connectors,and if that gets corroded,you may lose the ground,and the headlamps won't work.I'd start by checking that first.Find where the plow wiring harness plugs into the OEM truck headlamp plug.It should be somewhere behind one of the headlamps.