Truck/Trailer Lights Help

I’m stumped on this one……….

When I plug in my boat trailer lights to my F150, I don’t have running lights on the trailer, but the turn and brake lights work.

When I plug the same trailer into my wife’s Explorer, all lights work including the running lights.

So it’s something in my F150? Anyone ever experience this?

Eric

There is likely a fuse blown in the truck. Has happened to me in my last 2 F150’s.

Fuse in the box in the engine compartment.

Had same issue with mine a couple years ago. The Trailblazer was wired so that marker lights were on a separate fuse. I think the F150 I had many years ago was same. One circuit marked brake lights and the other trailer lights. Check your owners manual. Good luck. This kind of stuff drives me nuts!!

You know the trailer is OK because everything works when it’s plugged into your wife’s vehicle.

The problem appears to be with your truck. I’m guessing either a blown fuse or a bad connection in the wiring harness.

Rootski

Sorry ahead of time but this needs to be asked. Did you have the truck running lights turned on?

My guess would be the fuse on your truck. That fuse should be located in the big fuse box under your hood. For some reason on my f250 everytime I would plug in my tool trailer with the lights on it would blow that fuse so now I make sure my lights are turned off when I plug in the trailer.

Fuse

You have the tow package and there will be a seperate fuse set for the wiring harness off the back plug.

You can see the diagram in the owners manual

Dog

Also, you may have a connection problem where the tailer plugs into the truck –

Spray out and clean out.

Dog

Quote:

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Fuse in the box in the engine compartment.

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X2. Had the same issue on my F-150. The cause was the middle running light on the back of the trailer. It had a crack in it and would get water inside, which when enough water was in it, it would cause a short and blow the fuse under the hood. Replace the fuse, and if it blows again, I would look for a short at the plug on the truck.

X2!

Thanks to all. One 20A fuse and I have running lights!!

And I impressed the wife as well.

You have to ask your self why did the fuse blow? I’m sorry to say I feel it will happen again. I had the same thing happen last year. The tail lights would work fine when I left and not be working latter. I rewired the trailer with 110 extension cord last fall. I also replace the marker lights. My tow vehicle is only two yrs old so I am thinking that is not the problem. I am waiting to see if it happens this year.

I found that my Shorelander trailer had 2 wire male and female plugins inside the trailer frame about two feet before the tail lights. They were not plugged together all the way. They may have been shorting out when the trailer would hit a bump in the road. I am thinking that may have been the problem. I checked every inch of old wire and could not see any other problem. I will have to wait and see.