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My Jeep has an after market hitch installed with a 4 wire wiring harness. The pictured connector is present. What all do I need to do to upgrade the system to be able to tow a trailer with electric brakes? Plug and go? Also install brake control inside? Have dealer activate factory trailer brake capability?
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Well, I'm 70 years old with bad eyes so take this with a grain of salt. That picture, TO ME, looks like a 7 way flat RV plug AND MAYBE the innards, or part of the trailer plug that goes into it. Either that or it's a 7 way RV plug with the outer cover missing. Can't tell for sure and don't know if any wires are already hooked to it for lights and signals.

As for what all you would need depends on if your vehicle came with the wiring harness pre-installed for the electric brake controller......and if your current 4 wire harness is working properly for tail lights, brake lights, and turn signals. Some Jeeps have a plug taped up under the dash near the steering column and a baggie with a wiring pigtail for an after market controller in the glove compartment. If you do have the factory wiring harness you may, or may not have to have the dealer activate the brake controller once you have it hooked up. I've seen people say it worked soon as they hooked it up and others have said they had to have the dealer activate it. If you mount an after market controller and hook up power and ground to it and run the wire from the controller all the way back to the 7 way connector yourself then you would not need to have the dealer activate the brake controller.

Bottom line is you need to get a working 7 way plug with all the wires hooked up for your lights and signals PLUS the wire from an electric brake controller. Don't know what kind of trailer you a planning on towing but if you have to start from scratch the 7 way flat RV plug is pretty common on a lot of trailers and there is a 7 way ROUND plug that is common on work trailers and farm equipment that also has a pin out for a brake controller.

Probably haven't helped you much but one of the first things you need to do is find out for sure what that is in the picture, how many wires are going to it and do they work for lights and signals, and do you have the factory pre-wire for the brake controller or are you going to have to run your own brake wire from the controller to a rear plug.

Here is a link to the pin out for a 7 way flat connector and trailer plug.

 

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Agree with @Jerry – the picture looks like a 7-pin connector. It depends on what was originally installed. You can use a trailer wiring tester like the one below to determine what wiring is hooked up and working. A brake controller requires a separate wiring hookup under the dash spliced to several wires and one wire running back to the 7-pin connector. My 2012 WK2 had a brake controller connector preinstalled. Take as look at the instructions of a brake controller to see what’s involved. A trailer shop should be able to help.

 

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When I installed my hitch there was a harness I purchased off amazon that connected to the plug under the bumper. I have both 7 and 4 pin with that factory harness. Mines a 2018 so not sure if you have the plug tucked away. The dealer had to activate the lights.
 

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The connector behind the bumper brings the wiring to the OEM 4/7 Pin electrical plate that's part of the OEM hitch receiver kit. You may be able to order that part, which has a pigtail on the back, separately...talk to the parts department at a dealer, locally or online. The previous poster is correct that the wiring has to be enabled in the vehicle computer before it will work. There is generally a cost to this, about $100 has most often been mentioned to my memory over the years.

Please note that since you do not have Factory Towing, your limits are lower with a third party hitch. Factory Towing is much more than a hitch receiver and wiring...depending on the year, trim and engine, there are various changes to braking, electrical, suspension and cooling that are part of the Factory Towing option that provides full towing capacities. A WDH is also required above 350 lbs tongue weight/3500 lbs load per the manual.
 

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Discussion Starter #6
Thanks to all for the very helpful responses. Here are quotes from a couple of them:

"My 2012 WK2 had a brake controller connector preinstalled."

"The connector behind the bumper brings the wiring to the OEM 4/7 Pin electrical plate that's part of the OEM hitch receiver kit."

I believe the connector in my photo is factory installed. Based on the above statements, if my 2012 wk2 also has the connector under the dash preinstalled, should it be a simple matter of buying and installing a brake controller in the cab, getting a pigtail for the back, and having a dealer activate the wiring?

Thanks again for the info.
 

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Your 2012 does have the connectors installed. So yes, acquiring the parts and getting the dealer to turn on the wiring is what you need to do if you want/need to have lights and brakes for a trailer that has electric brakes. If your trailer has intertal/surge brakes, you do not need the controller as they are not controlled by your vehicle outside of emulating it's motion.
 

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The connector in the photo is for TOW wiring, but it is a vehicle electrical connector, not a TOW electrical connector. i.e. you can not connect your Trailers connector to it. You have to get the OEM Tow Connector to connect to the that electrical connector, but have you considered where you're going to mount it?

That OEM Tow Connector is designed to snap into the OEM Tow Hitch (the Mopar Accessory Tow Hitch is the exact same as the Factory TOW Hitch)..... .....if you have an aftermarket TOW Hitch, there is no where to mount the OEM Tow Connector, that you're going to have improvise......

If you need a brake controller, then yes you have connector under the dash to connect your brake controller to the vehicle.... either the Mopar or several different aftermarket offer a pig tail that connects between their controller and the vehicle factory connector..... ....that will control the Trailer Brakes through the factory TOW Harness.... ...but if you don't need a Brake Controller, don't think you have to have it for the rest of the circuits to work in the harness.....

Enabling, yes, just hooking up the OEM Tow Connector will NOT enable the circuits that are Controlled by the TIPM, that is controlled by Software.... ....the Dealer Can enable it using his software tools.... ....Look at the FCADiag and AlfaOBD threads, for less than a single visit to the Dealer you can purchase this software and use your laptop to enable the TOW Harness..... ....I used FCADIag to do this and it worked perfectly.....

You're talking about a Brake Controller and aftermarket TOW Hitch, pay attention to Jim's warning, the higher TOW rating for the WK2 don't come from the Hitch, it comes from the Factory TOW Prep Package, that adds extra engine cooling, higher amperage alternators, check your O.M., but it might say your max towing capacity is 3500lbs....
 
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