Greetings,

I just installed an electronic brake control unit on my 2008 Wrangler
Unlimited X. The electronic brake control unit required the install of a seven
pin (aka blade) that allows charging of my trailer battery. This final set-up
allows me to tow a 3500 trailer (I have an E1) with utilization of
an electronic brake control system and charging my trailer battery and/or
running my three-way refrigerator.

Some truths about this project:

i) The stock 07/08 Wrangler, even with the tow package, is neither equipped with
wiring for the electronic brake control nor the wiring for the battery charger.

ii) The Mopar 7-way trailer tow harness can be used, however, one still
needs to run the brake control and charge line to the front of the vehicle
and, ultimately, within the cabin.

Basically, here are the steps (I plan on posting my step-by-step images at a
later date). They do not provide exact detail, however, most of the critical steps with the details filled in by anyone with basic wiring experience.

1) Assuming that you already have the factory tow package, cut - yes, I said cut, the [almost useless] four wires that connect the standard 4-pin receiver and connect them to a standard $6 seven blade. Note that White is the ground (to be attached to a standard #1 location on a seven blade), White/Green is Left turn (attached to #5), White/Orange is tail lights (attached to #3) and White/Yellow is right turn (attached to #6).


Note: If you do not have the factory tow package then you have the choice of going with a $80 Mopar 7-way harness or a $15 standard 4-way harness.

Note: For those who have the factory tow package, one can re-use the 4-pin
mounting bracket by drilling tow holes in it to accommodate the seven blade unit. This seemed to provide enough stability to connect and disconnect the seven blade.

2) Run two 10-gauge wire (preferably black and blue) from the 7-blade to the front of the vehicle. I purchased a bundle of black and white 10 gauage wire from a leading e-internet trailer company for $0.89 per foot (I needed around 20 feet). I pushed the wire mostly on the passanger side of the car (following other wires under the car) and eventually up through to the engine compartment (just to the driver direction of the battery. As appropriate, I lined the already encased 10-2 wire in black automotive conduit.

3) Install two 30 amp auto-reset circuit breakers. I found that the protective sleeve of the battery harness was a good [only, really] spot. Two breakers are required to protect the car from the trailer battery and the battery to the electronic brake control unit.



4) Create a 10-gauge "bridge" wire between the breakers using two standard 10 gauge ring terminals. Also, make a 10 gauge wire (with ring terminals) to be connected to the positive terminal of the battery running from the breaker.

5) Connect the 12 volt wire (connected to blade #4) to a breaker and run the 12 volt [hot] wire from the second breaker to the inside of the cabin (again relying on the bridge wire between the breakers).

6) Continue the blue brake wire (connected to blade #2) into the cabin.

7) Create a 14 gauge wire linkage from the (-) terminal into the cabin. This will serve as the ground for the brake control unit.

8) Again protect the wires going into the cabin (and past the engine) with automotive conduit.

9) Fish all wires through the rubber plug (just in front of the driver side engine compartment) and down into the cabin. I found it impossible to push the wire through the rubber stopper. So, I pulled it out through the length of the wire and re-plugged it afterwards.

10) Mount the electronic brake control and connect the blue brake wire, black 12 volt wire and 14 gauge white ground.

11) Find the Jeep brake wire that is attached to the brake switch (I found it to be the White/Tan line, however, do not trust me - get a volt meter) and splice into this line with the brake control brake [red] wire. I used a standard splice lock (blue) aka scotch lock. This avoided having to solder a splice on my back while propped against the driver side seat. For the dry inside of the car, I think that these splice locks are fine.

12) Disconnect the the leads to the battery terminals and attach the (+) and (-) wires (one from the breaker, the other from the ground). I used 3/8" 12-10 gauge ring terminals for this step for the terminal side; connect the leads back to the battery terminal in the (+) (-) order.

14) Connect your trailer to your jeep and test left, right, brake lights, running lights; finally use the manual brake control and also depress brake brake pad to verify that the trailer brakes are working. As soon as you connect the trailer to the Jeep, you should see some sort of green light turn on in the brake control unit (I am using model T. 80500)

Like I said, I will post all of my images if people are interested. I was happy with this project as it took around eight hours and ended up better than my Honda Pilot job that was performed by a local RV shop.

Good luck!

 

When will they ever learn?

 

Let's see the pics

 

In addition to the pictures that I have added to the original thread, here are four more.

 

click free

 

how do you manage to get a trailer onto that ball with it being so close to the spare???
oh and welcome to the site and thanks for the write up

 

just installed my 7 pin i love it

 

The picture that I posted is a bit misleading... The ball mount that one can see in this image is actually a 12" length (measured from center of ball shank to center of locking hitch pin). This provides about ~4" or more of space between where the trailer lowers and the spare.

My original ball mount was 8.5" and that size, unfortunately, did interfere with the tailer. I know that one can find a 16" ball mount, however, I find that the 12" length unit works just fine.

Here is the final pic of the setup... ready for the white rim trail



-Regards

 

Thanks for the write-up Kachua. This information was helpful in understanding what some of the parts were in the Mopar 7 pin wiring harness installation.

Micah