How hard is it to add OE trailer wiring harness

DavidDulin · **Posted:** Mon Mar 30, 2015 9:44 pm

I just bought the OEM trailer hitch assembly from them (Love Field) - $177.00 SHIPPED. A steal. if it arrives by Friday I will be putting it in Saturday / Sunday, maybe by myself. Pair of jackstands to support the hitch while I get the bolts in?? Regarding the OEM harness, the install sheet seems to show a wire or wires routed through the firewall grommet and zip tied to a harness underneath, no connections. What's up with that?? I will be getting that in the near future.

The hitch will be used to carry either a Thule bike carrier or a step / bumper protector most of the time.

Erikg84 · **Posted:** Tue Mar 31, 2015 10:03 am

that wire, I believe, is used to connect to your trailer brake controller if you have one, or decide to install one in the future.

I installed the OEM hitch I got from Lovefield about a month ago. I suggest that you buy an extra bolt from Lowes or Home Depot and get a wire brush and some penetrating oil to clean out the holes before you try putting the hitch on. For the wire brush, I just used an old metal brush from my gun cleaning kit. It takes a bit of elbow grease, but it's worth the time.

edit: I can't type for seome reason today...
edit: *some... :banghead:

DavidDulin · **Posted:** Tue Mar 31, 2015 7:26 pm

good advice, thanks. I was planning on some WD40 or equivalent before shearing an undercarraige bolt. I usually break at least one thing (or get one injury) every time I open the toolbox.

what type of bolt does it take? I know 18mm but no other specs listed in the manual.

Erikg84 · **Posted:** Wed Apr 01, 2015 9:00 am

Same here... I'm accident prone...

I used an M12x1.75-35 grade 10.9 bolt and it worked perfectly. I found that it was easiest to spray them down with PB blaster (or equivalent) let it soak, scrub with the brush, put bolt in as far as it would go, take the bolt out and repeat the whole process until the bolt goes all the way through.

Drifter · **Joined:** Thu Feb 05, 2015 1:41 am **Posts:** 32

Simply ran a tap in and out while flushing with PB Blaster. Blew out the holes with air, greased the bolts and torqued them to spec.

Erikg84 · **Posted:** Thu Apr 02, 2015 8:54 am

that would work too, but I don't have a tap, and I don't have an air compressor (yet).

BKNY · **Joined:** Tue Apr 22, 2014 7:19 pm **Posts:** 13

Did you or do you plan on using Loctite on the bolts or would recommend?

Erikg84 · **Posted:** Thu Apr 02, 2015 2:13 pm

The bolts that came with my OEM hitch came with Loctite already on them.

DarkSport11 · **Posted:** Thu Apr 02, 2015 10:39 pm

Erikg84 wrote:

Same here... I'm accident prone...

I used an M12x1.75-35 grade 10.9 bolt and it worked perfectly. I found that it was easiest to spray them down with PB blaster (or equivalent) let it soak, scrub with the brush, put bolt in as far as it would go, take the bolt out and repeat the whole process until the bolt goes all the way through.

That's exactly how I did mine, worked like a charm. OEM bolts have Loctite on them already just torque to specs.

DavidDulin · **Posted:** Sat Apr 04, 2015 3:20 pm

DarkSport11 wrote:

Erikg84 wrote:

Same here... I'm accident prone...

I used an M12x1.75-35 grade 10.9 bolt and it worked perfectly. I found that it was easiest to spray them down with PB blaster (or equivalent) let it soak, scrub with the brush, put bolt in as far as it would go, take the bolt out and repeat the whole process until the bolt goes all the way through.

That's exactly how I did mine, worked like a charm. OEM bolts have Loctite on them already just torque to specs.

Installation is in progress. breaking Dremel cut off wheels by the dozen notching the bumper out.

Does the factory (rear left) tow hook bolt back in over the hitch assembly??

Bmxer524 · **Posted:** Sat Apr 04, 2015 8:00 pm

Metal cutters or a sharp razor blade should cut it easily. And I don't believe the hook goes back in. Buy a d-ring and receiver to throw in the hitch and you're set. Better off actually too.

DavidDulin · **Posted:** Sun Apr 12, 2015 9:16 pm

I ordered the OEM harness from Love Field, $111.00 shipped.

Installation is "NOT" as straightforward as the install sheet shows. Install sheet is for a Dodge Nitro, may be subtle differences between the two. For example, one of the first stems shows using a door panel tool to remove the taillights. Liberty's are held in with 10mm bolts. Install sheet shows securing the relay bundle to an existing harness in the jack area - my Jeep does not have an existing harness there, so I need to get some of the self anchoring cable tie clamps to pop into existing holes I also had to loosen up the hitch, drop it about 1/2" or so to feed the large 7 pin connector shell over the top.

When I got to the step where the harness gets routed past the muffler, then to the other side and into the engine compartment, I simply couldn't do this without a lift. My uncle opened his repair shop for me for an hour to use the floor jack, jack stands, etc. I got the front jacked up and onto stands and just didn't feel comfortable underneath - I still couldn't easily see what to do. I pulled the harness back, coiled it up, and secured it to the underside of the spare tire.

I brought it to Firestone to see if they could throw it up on the lift and just run the wire - too busy on a Sunday. Will try again during the week.

toy4everyseason · **Posted:** Sun Apr 12, 2015 10:00 pm

I did mine with the front wheels on ramps in the driveway. Wasn't extremely fun but I've experienced a lot worse under a vehicle.

JAGphoto · **Joined:** Thu Feb 27, 2020 10:43 pm **Posts:** 1

I realize this is an old thread, but the directions say you need to go to the dealer and have the harness purchase added to your vin and activated with their computer. Will the harness work without doing this? We have a 2012 KK.

How hard is it to add OE trailer wiring harness

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