I have a 1993 F-250 with factory wiring for the 7 prong trailer wire. My running lights quit working recently on the trailer. I took a battery and hot wired the D prong on the trailer and they work. I checked the D prong on my truck and it is dead. All fuses in the fuse box check OK. Is their another fuse somewhere in the line to the back of the truck? Any help would be greatly appreciated.

 

Just fuse D and the marker lamp relay.

Does the relay click when the light switch is pulled out?

 

subford, I'll check for the click when I get home from work. Thanks.

 

This may help:


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Thanks a bunch subford. I didn't get home til after dark today so it will have to wait til tomorrow. I feel much better after seeing your picture.

 

If you need a wiring diagram of this circuit just email me at the address below in my post.

 

It was just a 25 amp fuse in the distribution box. Thanks subford.

 

Just a quick question my 96 "clicks" when running lights are turned on does that mean it has tow package or do all trucks have the click? Dumb questions here sorry!

 

I don't know - all my Fords have had the factory towing package. They click. Subford will probably know.

 

Yes all 92-96 body stile trucks have the Trailer marker lamps relay with or without the factory towing package.
This relay will also control any of the extra marker lamps on the truck. The only ones it does not control are the parking lamps on the front and the rear corners.