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douglassoilco 12-20-2007 03:54 PM

Mopar Wiring Harness for Towing
I've purchased a Mopar tow bar and wiring harness to tow my JK behind my GMC Pickup or Ford make the brake lights, driving lights, and turn signals work on the JK when the towing vehicle signals/lights are turned on. The wiring harness was installed by my local Jeep Dealer.

The Mopar seven wire harness does not work on the Factory GMC or Ford seven wire receptical. No lights come on. But by chance, I asked the service manager to try the seven wire harnes from the JK to a Dodge
Pick up. All lights worked perfect! Is there a diffewrence between Mopar/Chrysler recepticals and the recepticals mounted on GMC's and Ford's? My local Jeep dealer has yet to find or determine an answer.

Has anyone experienced this same problem?

Ken Douglass

whitebuffalo 12-20-2007 04:22 PM

all 7 pins should be the same. i would be looking for a bad ground somewhere

douglassoilco 01-07-2008 02:02 PM

Do Not Purchase the Mopar Jeep Wrangler "RV" Tow Harness. This Mopar Part, ONLY works with a towing vehicle that is a Chrysler Product. It will not work on a 7 prong wiring plug on a GMC Pick Up, or a Ford Expedition, or a GMC Envoy. We've not tried a Winabago or Blue Bird RV!
I have found no way to communicate with Mopar direct. I am at the mercy of my Jeep Dealer, who could care less, because he's already made the Jeep sale!
It would be refreshing to speak to Mopar so that they could learn from the customer which parts work and which parts appear to be unacceptable out in the "field."
Maybe Mopar is a member of this Wrangler Forum.............?

jdrogers 01-08-2008 11:27 PM

Did you actually "test" the wiring harness installed on your JK? The connections on a seven wire connector are pretty standard. Here is a good resource for wiring trailers.


The wiring for the connectors are:



Try just using a wire connected to the positive battery post and touch the appropriate connector pins to see if the lights work properly on your JK.

I know my local dealer has sold several of these wiring kits to people with RVs and have not had any issues.

I wired my JK for towing using diodes since I already had them (and the wiring kit was not available back in November 2006). These are the connections I used since my Bounder matched these connections and so I could tow my JK with other tow vehicles.

douglassoilco 01-09-2008 03:13 PM

Yes, the dealer service tech did. All outputs are correct comming INTO the "under the dash " Jeep wiring harness correctly. We suspect the "under the dash" T Harness to not be accepting any inputs from the towing vehicle to the Jeep computer. Remember, we feel like we've ruled out the Mopar 7 prong plug and harness as being faulty because it works correctly on a Dodge Pickup.
However, I'm having to trust the dealer's technician as having made all proper tests.

If we don't get any help on this soon, may I contact you as to who YOUR Jeep dealer is and put them in contact with my Jeep dealer?

jdrogers 01-17-2008 07:23 PM

Did you get this resolved? If not there are a couple things I have come across...

1) Just unplug the connectors under/behind the dash and plug them together again. It seems they are "touchy" to being connected properly.

2) Make sure your tow vehicle (RV or something?) is providing +12 volts on the "battery charge" pin shown in the pictures above. The Mopar harness uses this power to operate the lights in the Jeep.

Hope this helps.

douglassoilco 01-21-2008 10:05 AM

We are not resolved yet. I've been sucessful in obtaining a Chrysler Inquiry number and opened a file. Now the dealer has to respond. The dealer proposes that we put a Ford, a GMC, and a Dodge in his shop along with the JK and new Mopar harness for further testing. He says he will have the "factory" on a conference call with the service manager and his tech to try to figure out where the problem is.
Thank you for your concern and interest. I'll keep you and the forum informed.

douglassoilco 02-26-2008 11:47 AM

mopar "rv" towing wiring harness
Sorry it's taken so long to get to the bottom of this delima.
So far, at my $75 expense, the Jeep dealer put a Chevy Pick up, factory wired for towing, next to a Dodge pick up wired for towing , and plugged in my Jeep. The Dodge activated all lights on the Jeep but the Chevy did not. THEN, the Jeep Dealership technician tested the "out put" prongs of the 7 plug female receptical. 12 volt power comminmg out of the Chevy. This is position 4, or a black wire, as per Mr. JD Rodger's diagrams. All works fine when position 4 is hooked up to the battery, but my General Motors Dealer ship had to do it for me on my personal GMC pickup.

Now, we will go to the Ford Dealer, to see what they have to do to my Expedition for proper Jeep towing.

All persons involved have been shocked at these results. The Ford, General Motors, and Jeep dealers all had never heard of such a mismatch with "FACTORY WIRED TOWING PACKAGES."

jdrogers 02-26-2008 06:55 PM


Originally Posted by jdrogers (Post 183308)
... 2) Make sure your tow vehicle (RV or something?) is providing +12 volts on the "battery charge" pin shown in the pictures above. The Mopar harness uses this power to operate the lights in the Jeep...

Too bad you were not able to get the +12 volt pin tested back in January... ;)

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