I have a 98 Expedition with a tow package. While towing my Seadoo the trailer had a flat and crushed one of the lenses and light bulbs on the trailer. I replaced the lens and light bulbs but now all I get are running lights when the truck lights are on. I don't get brake or turn signals at all. Could I have caused some damage within the truck? I checked all the trailer wiring and all checks good. Is there a relay that controls the trailer lights? The lights on the truck function well.

 

Did you check all the fuses to make sure none of them blew. I would also re-check the bulbs in case they may of blew as soon as you stepped on the brake and or signal. This happened to mine, I then rechecked that everything was connected and dry and put a new bulb in and it worked.
Good luck

 

I have all new light bulbs and have checked the fuses. All seems to be in order but I still don't have signals or brake lights on the trailer. All running lights work fine on the trailer but no signals.

 

I know you said you checked the wiring but did you make sure they were grounded properly? Not being grounded caused the problem I had last year with the lights on my boat and it sounds just like your problem. I had running lights but when I hit the brakes or signals they all went out.

 

Trailer lights can be agravating sometimes, especially ones that you dunk in water or drive on salted winter roads with . I've resorted to hard wire grounding each light to the trailer frame to get some reliability. The factory set ups work great for about 6 moths in harsh conditions .

 

The ground is hard wired to to the trailer and continuity checks good. When I use the turn signals or brakes I don't loose the running lights. You're right, we have to stay on top of these trailer lights that go in the water and I have but for some reason I don't think I'm getting the signal from the truck. I set the meter right on the receptacle and I get the running lights voltage but no fluctuation for the brakes or turn signals. Is there a separate relay or flasher that controls this? I don't have a repair manual for this truck and the owner's manual is not much help. I hope someone out there knows something about how this works within the truck.

 

You can buy a tester for about $2 at any auto parts store and that would tell you if the problem is with the truck or the trailer wiring. They just plug in to your trailer light hookup at the rear of your truck. Canuk is definitely right, trailer lights seem to be a pain more often than not. Hope you get it figured out.

 

The bulbs on my trailer have two filaments. One for running lights and the other for brakes and signals. Did you replace them with the same types of bulbs that were in them before? I can't come up with much else but I'll keep thinking.

 

I have the same problem , same scenario and Im frustrated as hell. I build boats for a living, so I use it alot. Last weak everything but the running lights stopped working. Ive tried All I can think of , is there a relay, or a fuse I know not of? Roduz, did you get yours working please let me know.

 

Did anyone find the solution to this problem? I just bought a 2003 F150 Super Crew and I plugged it into 2 different trailers and have the same results. When I do not have the truck lights on, everything is fine (turn signals and brake lights work fine). Once I turn on the lights, the trailer lights come on very bright. As they are fully eluminated, pressing the brake or turning on a signal has no impact. The lights remain on full bright.

I really need help, I took it back to Ford and they said all is well. My next step is to take the trailer with me.

 

On my navigator it was definetly a blown fuse, a 20 amp that was located under the hoo on the driver side fender seven inches or so from firewall. there wer five fuse slots, four were used. the two to the rear (firewall side) were the running lights and signals for the trailer circuits. I don't have any info for the F series but on nevs and expeditions that would do it. i also had some wire chaffing under carriage side, but it was minimal andI fixed with liquid electric tape, I would check there also. hope it helps.

 

Bout ne a new used F-150 SpuerCrew Yea! Thraded my Ranger in on it. The ranger had a 4 in connector and worked fine however the Screw has a 7 pin and a 4 pin hookup and the darn thing is not working at all!!! I know it is not the traler as it was woking last week. I love the remote locks as they flash lights to check Just lock the doors and wow lights. Press again and lights and horn sound! Press again and the neighbor yells at you

 

Usually trailer problems are with the trailer. Make sure you didn't have a wire crush or chafe to the trailer frame or something like that. I figure you're aware that the trailer tow harness has its own fuses, which ought to be in the fuse panel that's below the instrument cluster. Actually, it's kind of smart, because in the old days a messed up trailer wiped out the truck's lights as well. It doesn't anymore.

Oh, the trailer harness also depends on a backup light relay, a battery charge relay, a battery charge fuse, and an electric brakes fuse, all of which are in the fuse panel found on the driver's side fender/ That ought to only affect RV trailers and electric brakes, though.

Realgun - Are you sure that thing is pushed all the way into the 7-pin? Mine had trouble with that until it got broken in. The newer 150s came through with both a 4-pin and a 7-pin mounted next to each other, BTW. You'd have to visit Mr. Ford for that fix though. Otherwise, you might have a dead fuse in the same place.

jdrkdr - You could have had the two little filaments in the bulbs break and short each other so that they're both lighting up by shorting each other out. I see this happen occasionally with my own stuff. Otherwise, I'd bet on trailer wiring shorts.

 

i had the same exact problem. there is a serperate fuse for the brake and signal lights. It is located in the small black box on the right hand side of the engine compartment.

 

Actually I hooked it (my trailer) again and got left turn and brake only.
I know the fuse is out, I looked at the broken filament in the fuse panel under the hood, probably the right side. Now all I need is running lights for night driving.
I rewired the trailer less than 8 months ago with new lights and did not get to dunk it yet. The boats not finished. It was working fine the other day with my Ranger on the 4 pin wires.