Can a JK run both the flat 4 pin and 7 pin trailer light hookup at the same time?

[Longtallsally]

Since I see so many folks around here running trailers, I thought I'd pose the question as I have an issue with the trailer lights on both.

The Jeep is a '12 JKUR with the OEM towing package (installed at the factory) and the OEM trailer brake harness (plug and play and installed by me).

Obviously I've had this stuff for quite a long time, but only now am realizing an issue what I thought was a ground in the trailer. I've been doing most of my towing with the camper recently and only when the headlights are on, the right side brake light on the camper is a scoshe more dim. When I turn the turn signal on, it flashes, but both filaments don't work (it goes from fully on to off as opposed to on, then brighter for the indicator).

Both sides on the Jeep and the left side for the trailers work perfect. When the headlights are off, everything works perfect- including both brake lights.

I figured this was just a ground issue on the camper (7 pin with trailer brakes), but recently needed to use a utility trailer and the exact same behavior. I also use a hit carrier for the dirt bike that has lights and it does the same thing.

So I've done a number of configurations to test:
- pulled everything and hooked the OEM harness just into the trailer (no OEM lights)- same thing
- pulled just the 7 pin harness out to where it was when delivered- same thing
- pulled the 4 pin harness and used just the 7 pin- same thing

I've got an an appointment with the dealer here in a bit, but I have a hard time that 3 different trailers (4 total) used on the Jeep have a ground problem or the like. In addition, I get no faults from the brake controller.

Anyone else run into anything like this?

 

[madmax718]

you can try a long wire and connect the ground to the battery directly. See if this affects anything..

 

[Longtallsally]

That is a good suggestion. Since discovering this, in my research a number of folks mentioned the little Wallyworld 4 pin tester for everything. I think the brake controller pretty much serves that purpose and shows no errors, but pending what the dealer says, it might be an option for my own testing.

All this stuff is plugged into the left side tail light assembly and I have to stress is ALL OEM.

 

[sickchilly]

I mounted this in the stock location and ran an extra wire/ground from my trailer break controller. Then I had both 4 and 7 pins available.
http://www.uhaul.com/MovingSupplies.../7-Way-Spade-Type-4-Way-Flat-Connector?id=718

 

[Longtallsally]

Already have both and both are OEM- just in separate connectors.

At the dealer this morning they initially thought the ECM needed to be programmed to handle the harness, but then realized it didn't. They are now having a journeyman electrical guy take a look.

I couldn't have done something wrong as the fully OEM install of the tow package behaves the same way (if I pull the trailer harness completely out of the equation) in working incorrectly with the headlights on.

 

[JKDetonator]

Mine has the trailer tow package which came with the 4 pin connector. I purchased the 7 pin connector and had the service department install it. Where is everyone installing the brake controller? Space on the dash is limited... Let me know; pics would be helpful! Thanks!

 

[sickchilly]

I hung mine (a Tekonsha Prodigy P2) next to the ODB port using the supplied bracket to the bracing under there.