7 pin trailer wiring

[89 MJ]

This Sunday, my band has a performance in which we will be using our car trailer as a stage. We will be playing at a car show, so I am bringing my MJ. I am thinking, it probably would make sense to use the MJ to tow the trailer and then my parents could bring whatever vehicle to the show. 
Our trailer has electric trailer brakes though, so it has the 7 pin connector. I know I could just use an adapter, but I think it would come in handy in the future to have the 7 pin connector, and I will have to go over a large hill to get to the show. 
How many of you have installed a 7 pin connector in your MJ? How did you go about doing it?

Thanks in advance. 

[89 MJ]

I am going to buy a connector this afternoon and start on it. I’ll report back and then create a write up. 

[MiNi Beast]

Well my friend its more then just the connector. You would most likely have to add a brake controller to ensure you are utilizing the 7 pin setup properly 😉

Furthermore do you need the brakes for a small trip and one hill? Umm simple enough to just get a 4 pin adapter so you have functional lights atleast and I think that would be suffice for the trip intended. 

[coheed]

I've bought a 7 pin for my truck and the Comanche bed trailer I'm building as I want brakes on it. You'll need a stand alone brake controller to utilize the trailer brakes.

 

As far as wiring find what wires do what on the trailer and match them to the corresponding wires when you put the connector on the truck. I plan on making a jumper kinda like @88mjsally does out of a spare tail light harness I have.

 

 

[89 MJ]

11 minutes ago, MiNi Beast said:

Well my friend its more then just the connector. You would most likely have to add a brake controller to ensure you are utilizing the 7 pin setup properly 😉

Furthermore do you need the brakes for a small trip and one hill? Umm simple enough to just get a 4 pin adapter so you have functional lights atleast and I think that would be suffice for the trip intended. 

The plan is to install the controller and all of the associated goodness. It’s not a small hill either, my truck won’t pull the hill empty in 5th. Plus at some point I would like to get a camper to have behind the MJ, and I’ll probably need one then. 
I did consider just getting the adapter, but the 4 pin connector has been giving me issues, so rather than fix that, we figured we might as well upgrade. 

[89 MJ]

Just now, coheed said:

I've bought a 7 pin for my truck and the Comanche bed trailer I'm building as I want brakes on it. You'll need a stand alone brake controller to utilize the trailer brakes.

 

As far as wiring find what wires do what on the trailer and match them to the corresponding wires when you put the connector on the truck. I plan on making a jumper kinda like @88mjsally does out of a spare tail light harness I have.

 

 

I’m aware that I need the controller, that isn’t the part I’m worried about, I was more so wondering if anyone had installed one and wondering the route they went with it and whether or not they got rid of the 4 pin connector. 

[coheed]

Just now, 89 MJ said:

I’m aware that I need the controller, that isn’t the part I’m worried about, I was more so wondering if anyone had installed one and wondering the route they went with it and whether or not they got rid of the 4 pin connector. 

The receptacle I bought has a 4 pin on one side and the 7 on the other, let me see if I can find it.

[coheed]

Here's what I bought. Trailer connector

 

It says it's a custom fit, but let's be real. I also ordered a new FEY bumper cause my stock one will be going on the trailer. I plan on cutting out a hole and mounting this next to the plate instead of hanging down.

[MiNi Beast]

4 pins are lights already have that figured replace what you got, 3 other wires go to controller in cab run it how you wish,  

[Sir Sam]

Oh man funny timing. I just spent most of my last weekend adding a 7 pin connector to the MJ and wiring up the MJ trailer. 
 

if you already have a working 4 pin setup then it’s a fairly easy matter to hookup a 7 pin. I used one meant for a Jeep that had both 7 pin and 4 pin on it. 
 

https://www.amazon.com/your-orders/pop?ref=ppx_yo2_mob_b_pop__np_7_pp&orderId=111-2039599-6284223&lineItemId=mjpkrwlupnmvsny&shipmentId=DtDwqjfkj&packageId=1&asin=B000CMHVF8

 

 

 

you will need to run a wire to the front for the electric brake controller, a 12v wire to your battery, a reverse wire. 
 

I had a helluva time since I have XJ style lights and needed to make a combiner for the brake and turn, you shouldn’t have that issue with stock lights. 

[Sir Sam]

1 hour ago, coheed said:

I've bought a 7 pin for my truck and the Comanche bed trailer I'm building as I want brakes on it. You'll need a stand alone brake controller to utilize the trailer brakes.

 

As far as wiring find what wires do what on the trailer and match them to the corresponding wires when you put the connector on the truck. I plan on making a jumper kinda like @88mjsally does out of a spare tail light harness I have.

 

 

that’s exactly what I did for my MJ bed trailer, I even got brake backing plates that use parking brakes hookup so I can have a hand brake on the tongue I can set to keep it front rolling around on me. 

[89 MJ]

Thanks guys! That was exactly what I was looking for. Plans changed and we won’t be needing the trailer for the band, but I still want to add a 7 pin at some point. 

[Sir Sam]