so how are you testing with the trailer plugged in? Where are your leads on your meter going to? At the trailer lights? Does this problem happen with any other trailers?

if the trailer is plugged in and you throw it in reverse, does it say that the trailer is connected or do your reverse parking sensors still avtivate?

If the truck doesn't sense a trailer is plugged in (i.e. a poor connection with the plug) it won't send the full power to the plug.

 

removed - wrong thread

 

I'm testing the module under the dash... driver foot well. I can put one lead on the brown wire, my other to a ground....I get 3.4 there also.

No other trailer to test with at the moment, but my trailer was checked with another truck...all good for him.

I have all other functions.

Here's where I'm getting my info for a possible bad module.....

 

Have you checked the owners manual directions on hooking up the trailer, pressing the brake lights and adding the trailer to the trailer menu?

 

Yeah, module might be your issue. I just checked my truck with my meter, no trailer hooked up. Between the running lights and ground at the plug, I have 0 volts. As soon as I turn my lights on or lock the truck, I get 12 volts whenever my parking lights are on. After the lights shut off, It stays at 3 volts for a couple seconds and goes to 0...

Hopefully that helps your diagnosing.

 

You need one of these https://www.levittownfordparts.com/s...z-14489-a.html.
we sell alot of them. There corrode internally.

 

Done that.

If you have time or anyone lol.... check you brown wire on the trailer control module, that's shown in the video I posted... is yours 3 ish volts?

Mine looks mint.... took it apart, and I'm getting the 3.4 volts even before the 7 pin plug, so the plug is not the problem.

From what I read, I should have 12v coming from brown wire on the trailer control module that is located under the dash, driver side....and I still get 3.4v

 

I'll check it tomorrow. Currently raining and it's dark out.

That brown wire off the controller should be going straight to the plug? Either way my plug had 12v anytime my parking lights were on. No trailer connected, no truck running...

 

I believe that brown wire runs from the control module, right to the back of the 7 pin for running lights.

Thanks!

 

Adding a trailer the truck's menu will have nothing to do with functioning lights. I pull a trailer almost every day for 6 months of the year. Every time it asks me about adding the trailer I push "exit". The trailer lights all function as they should on all 5 of my trailers. 4 are 7 pin and one is 4 pin.

 

I had to purchase this adapter for the truck to recognize my truck camper. The running lights and brake lights are LED and don’t pull enough power to engage the truck electrical circuits.

 

Just checked for ya, at the brown wire on the module and a ground, 12 volts whenever the parking lights were on. No trailer hooked up, no key in the ignition, and in any position that gave me lights...

Went to 3 volts after the lights turned off. Dropped to 0 after a bit...

 

Well that was very kind of you to check into that for me.... I think I found my problem then, I only have 3.4v I think I'm going to cut that brown wire and run 12v to the back, just to be sure. Thank very much Norcalpr

 

A new reprogramed module is going to run me $300, so I may just run 12volts to the module's brown wire on a switch.... with a in-line fuse. I don't have up-fitter switches. Anyone recommend a fuse to run off of?

The trailer is only a 7x16 enclosed and all led, I would only be lighting the running lights. I could run a tap fuse from something in the passenger kick panel?

2017 F350 Plat 6.2

 

My boat trailer has LED lights all around and I don't have any issues with the lights and the truck not recognizing the trailer.