No power to trailer running lights

[RangerDanger_]

UPDATE: 10/22
Trailer running lights issue was solved by replacing # 25 fuse, located in slot 71 in the lower fuse box, under the hood.

There seems to be a confusing info on here about the factory installed tow packages TRailer Module. The trailer power connector still has a fuse that can blow. Changing it fixed my issue.

[SOLVED] I have the factory installed tow package, but I’m having an issue with my trailer running lights. The brake lights and turn signals work, but running lights don’t. They did for a minute, but I feel like something shorted, and I cannot find a fuse to check or replace.. Been searching the forum and found a few little bits of info, but nothing that really helps.

From what I understand is that the bottom fuse box under the hood doesn’t have fuses that control the trailer lights and that the fuses indicated in the owners manual are for aftermarket installs, another member mentioned something about a Trailer Module that, which I have no idea what or where that is? Really need some help with this, I feel like this is something simple that I could fix myself and not have to take it in.

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[Big Blue]

I have the factory installed tow package, but I’m having an issue with my trailer running lights. The brake lights and turn signals work, but running lights don’t. They did for a minute, but I feel like something shorted, and I cannot find a fuse to check or replace.. Been searching the forum and found a few little bits of info, but nothing that really helps.

From what I understand is that the bottom fuse box under the hood doesn’t have fuses that control the trailer lights and that the fuses indicated in the owners manual are for aftermarket installs, another member mentioned something about a Trailer Module that, which I have no idea what or where that is? Really need some help with this, I feel like this is something simple that I could fix myself and not have to take it in.

Yes, with the factory tow package you will have a TRailer Module (TRM) it controls the trailer lights and the power to the 12v pin in the 7 pin trailer connector. I would check you trailer lights for a loose or broken wire to the running lights. Maybe a bad ground.

 

[RangerDanger_]

Yes, with the factory tow package you will have a TRailer Module (TRM) it controls the trailer lights and the power to the 12v pin in the 7 pin trailer connector. I would check you trailer lights for a loose or broken wire to the running lights. Maybe a bad ground.

I feel that it’s definitely something going on with the trailer connector, as I hooked them up to another truck and they worked fine. Is the TRM accessible? Does anyone know where it is?

 

[NotBudule]

Have you tried both plugs on the truck ? Did you hook back to your truck after they worked on the other truck ?

I'd try the 4 pin , be easier to test with anyway , it's almost always the trailer...

 

[deleriumtremor]

If you have a DVOM or a 12v test light you can check to see if there is power to the running lights pin on the truck. I believe it is Pin 3 on the truck (like 11 o’clock when looking at it), I think.

Make sure your lights are on when you check it.

 

[cfhgarza]

I feel that it’s definitely something going on with the trailer connector, as I hooked them up to another truck and they worked fine. Is the TRM accessible? Does anyone know where it is?

The TRM is just a PCB (computer board) in a case. There's not really going to be anything repairable on it. I don't know where it's located.

Check your trailer harness for corrosion

 

[ATMofMN]

I was having the same problem. Thank you so much for your solution. Would have taken weeks just to get my truck to the dealer to look at the wiring. Had to watch a few videos on how to get access to the offending fuse, but I got it.

 

[QuickSilver]

If, like me you are wondering where the power distribution box is, I found this:

Ford ranger power distribution box

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