I was just drivign along with my trailer lights/brakes working fine, then, I started the truck again and noticed no lights or brakes on the trailer, though lights were working fine on my truck. I tried finding the fuse but all I get is, it seems there is a fuse for the trailer lights, and another for trailer brakes, somewhere near the starter relay, both 20 amps. I can only find one yellow wire leading to the relay with a fuse, and it's a 30 amp, and it looks just fine.

Any suggestions?

 

The wording of your post is a little unclear to me so I'll try to answer the best I can.
It sounds like your having trouble finding the fuse for your trailer lights so here you are.

#4 is your trailer lights fuse (25 amp)
#21 is the fuse for your trailer brake controller (30 amp maxi)

 

Sounds like you lost the ground to the trailer.

Anyway it is Fuse Link "G" coming off the starter relay on the passenger fender for the marker lights on the trailer. Fuse link "G" feeds the relay for the marker lamps. It is 20GA Blue and not 20 Amps feeding the yellow wire.

The brake lights are fused in the fuse box on the safety wall in the cab. But if your brake lights work on the truck then fuse #1 is OK.









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For whatever reason, I'm not allowed to post attachments, so i can't post the picture I took. But I looked all over the engine compartment and I cannot find a fuse panel. Where would it be? It's a 91 F250, 460.

However, I did look around the starter relay and notice a bunch of small blue wires around the battery that get fed into a yellow wire that has fuse links in it. One of these blue wires was completely burnt and disconnected. Could that be it? I did notice a little bit of burning smell when driving it last but couldn't tell if it was someone else's car, and it didn't last long. This wire may have been burnt for a very long time.

 

There is no fuse panel in the engine compartment of a 1991 truck.

I would say that the burnt fuse link is one of your problems. You might want to sub it out with a 20 amp CB for testing till you find the short in the trailer.

 

There is no fuse panel in the engine compartment of a 1991 truck.

I would say that the burnt fuse link is one of your problems. You might want to sub it out with a 20 amp CB for testing till you find the short in the trailer.

 

I guess I thought you had a later truck. Without more informating in the OP it was a shot in the dark. So when you say "trailer lights/brakes" do you mean trailer parking lights and brake LIGHTS or trailer parking lights and BRAKES? Or both?

 

Nothing was working on the trailer at all. No light, no brakes. Also, I knew it was the truck causing the problems because I took a test light to the trailer-plug in at the back of the truck, and I wasn't getting any juice to any of the contacts. I also lost my blinkers on the truck.

So what I did was go get a new flasher. Turn signals still didn't work. Then I put another fusible Link where the wire burnt up. I was now getting electricity to one of the contacts at the trailer hook-up. Progress. But still no turn signals. So, I looked, and the fuse under the dash, for the turn signals was shot. Then, I noticed I had no brake lights (though I did have them yesterday even after my trailer lights stopped working). So I found out that fuse was bad too and replaced it.

I'm pretty sure my trailer lights are going to work again, but concerned I have electrical gremlins on the truck, if I'm blowing fuses.