Trailer lights issues
Thread Starter
Junior Member
Joined: May 2026
Posts: 2
Likes: 1
Trailer lights issues
I have a 2013 f150 xlt and i cannot for the life of me get my trailer lights for my boat to work. Using the 4 pin connector they just wont come on.
used the multi meter to check both the truck side and the boat side and everything reads as it should.
connected my boat to a different truck and it works fine. Connected a different trailer to my ford and it works fine, but the boat trailer wont work with my ford. Ive tried chasing the ground and resecuring it multiple times.
used the multi meter to check both the truck side and the boat side and everything reads as it should.
connected my boat to a different truck and it works fine. Connected a different trailer to my ford and it works fine, but the boat trailer wont work with my ford. Ive tried chasing the ground and resecuring it multiple times.
Senior Member
Joined: Oct 2016
Posts: 1,682
Likes: 565
From: Connecticut
A volt meter isn't always the best way to test the circuit as you can read read voltage but you may not be able to supply the current due to corrosion at a connector.
I like to have a test light handy for that stuff with a filament bulb to know it draws some current.
(if they all haven't gone to led)
That you said another trailer works on your truck, I suspect you may have a poor ground.
Take a test wire from your battery negative terminal and bring it around back so you can put your ohm meter from that test wire to the ground pin on the truck 4 pin connector.
See what the resistance is.
My guess is it should be less then 5 ohms.
That the other trailer worked may have been from a ground through the ball and hitch.
Try it and let us know what you find.
I like to have a test light handy for that stuff with a filament bulb to know it draws some current.
(if they all haven't gone to led)
That you said another trailer works on your truck, I suspect you may have a poor ground.
Take a test wire from your battery negative terminal and bring it around back so you can put your ohm meter from that test wire to the ground pin on the truck 4 pin connector.
See what the resistance is.
My guess is it should be less then 5 ohms.
That the other trailer worked may have been from a ground through the ball and hitch.
Try it and let us know what you find.
Last edited by Newbie 5; May 9, 2026 at 09:39 AM.
Senior Member
Joined: Aug 2023
Posts: 172
Likes: 40
Personally not super electrically inclined I’ve been challenged over the years to get better and learn some troubleshooting. For me, if the problem is really strange and seems to defy explanation…the reason is somewhere in the ground side.
Thread Starter
Junior Member
Joined: May 2026
Posts: 2
Likes: 1
Fixed
A volt meter isn't always the best way to test the circuit as you can read read voltage but you may not be able to supply the current due to corrosion at a connector.
I like to have a test light handy for that stuff with a filament bulb to know it draws some current.
(if they all haven't gone to led)
That you said another trailer works on your truck, I suspect you may have a poor ground.
Take a test wire from your battery negative terminal and bring it around back so you can put your ohm meter from that test wire to the ground pin on the truck 4 pin connector.
See what the resistance is.
My guess is it should be less then 5 ohms.
That the other trailer worked may have been from a ground through the ball and hitch.
Try it and let us know what you find.
I like to have a test light handy for that stuff with a filament bulb to know it draws some current.
(if they all haven't gone to led)
That you said another trailer works on your truck, I suspect you may have a poor ground.
Take a test wire from your battery negative terminal and bring it around back so you can put your ohm meter from that test wire to the ground pin on the truck 4 pin connector.
See what the resistance is.
My guess is it should be less then 5 ohms.
That the other trailer worked may have been from a ground through the ball and hitch.
Try it and let us know what you find.
Senior Member
Joined: Oct 2016
Posts: 1,682
Likes: 565
From: Connecticut
I know what you mean.
When I have changed trailer lights or put in a new harness, I always run a new ground wire from front to back so I dont have to depend on the quality of the trailer to have a good ground connection.
It makes trouble shooting much easier too.
I'm glad you figured it out.
When I have changed trailer lights or put in a new harness, I always run a new ground wire from front to back so I dont have to depend on the quality of the trailer to have a good ground connection.
It makes trouble shooting much easier too.
I'm glad you figured it out.