Nissan Tow Package Wiring Harness 118266/118267 - 7 Way Harness Installed and Electric Brakes Locked

Technical Bulletin

SUBJECT/Summary: Installing Nissan tow package wiring harness 118266/118267 on 2005-2013 Nissan Frontiers and Xterras, 2005-2012 Nissan Pathfinders, and 2009-2013 Suzuki Equators.

PROBLEM: The electric brake and battery charge wires in the main harness are reversed on a small number of Nissan and Suzuki vehicles with factory tow package wiring. This issue has been found on very few vehicles but includes all models that use the 118266 and 118267 harnesses. The reversed wiring will cause the trailer's electric brakes to lock as soon as the trailer is plugged into the vehicle's 7-way and the vehicle's ignition is in the run position.

SOLUTION: If this occurs, determine whether the problem is with the vehicle or the trailer. First, disconnect the trailer's plug and the electric brake control from the vehicle. Next, verify the vehicle's 7-way functions; specifically the battery charge pin (#4 in the diagram), and the electric brake pin (#2 in the diagram) with a test light or voltmeter to ensure the functions are correct.

Isolate The Source of The Problem

To test, start the vehicle, attach the test light or voltmeter to ground, and touch the probe to the electric brake and battery charge pins one at a time, noting whether the light illuminates to indicate that power or voltage is present. If power was NOT detected on the electric brake and WAS detected on battery charge, the problem is with the trailer. If power WAS detected on the electric brake and NOT on the battery charge, the vehicle harness is reversed, and it will need to be repaired.

Repair The Connector

To repair the connector, choose one of the two repair options described below. Note: You may find it easier to repair the 2-pin black connector that contains the black and blue wires if you remove the 7-way connector.

Repair Option 1

This option is the best for the longevity of the harness because no splices are used. For this option you will need a small screwdriver and a pick tool, a terminal release tool, or a similar tool.

Remove white retainer from black housing

First, remove the tape that attaches the conduit to the wires and pull the tubing back. Then remove the white retainer from the black housing by inserting the screwdriver between the housing and retainer. (Note the orientation of the retainer in the housing for installation later.)

Turn the connector over. Starting at the inside of the connector, insert the tool into the connector until it stops. Twist the tool outward then put downward pressure on the wire assembly in which the wire and connector will slide out. Repeat on both sides.

dismantled Nissan and Suzuki OEM wiring harness

With the harness unpinned we are left with three pieces, the housing, the retainer and the harness. If the white gasket comes loose from the terminal it can be reinserted later during assembly.

Reassembled Nissan and Suzuki OEM wiring harness

With the locking tab up, reinsert wiring as shown. Ensure white gaskets are fully seated, replace the retainer, then reinstall the conduit, taping at the connector.

Repair Option 2

This option requires cutting both wires, then swapping and reattaching them. The best ways to ensure a proper connection and long life of the harness is to use either butt connectors or solder. In both cases, you should seal the splice with shrink wrap tubing. Begin by removing the tape and then pull back the conduit. Offsetting the splices will allow for both connectors to fit inside the conduit when finished. Measure 3" from the back of the black connector and cut the blue wire. Then measure 4" from the black connector and cut the black wire. Then cut the black wire again 2" from the back of the black connector. Discard the short section of wire, flip the connector 180 degrees and reattach the black wire to the blue and the blue to the black (make sure the shrink wrap is on the wire before connecting).

Length measurements on Nissan/Suzuki OEM Wiring Harnes

Nissan and Suzuki OEM wiring harness showing reversed wire colors

Using this method will allow the wiring to be completely concealed in the conduit, and it's weather tight.

Nissan and Suzuki OEM wiring harness showing wire colors after being reversed

Reinstall conduit tape at the connector, near the splice.

Bulletin Date: 03/04/2014

Bulletin Number: TB14-02

Melchor B.

3/23/2022

Please make a video on this repair. Your loyal customers will really appreciate it. Thank you !

Les D.

3/23/2022

@MelchorB thank you for your suggestion. With many thousands of parts it is just not possible to create a video for each of them. I will forward your request to our video team for their consideration. Thanks for being a loyal customer.

Jeremy C.

8/5/2023

Ditto on this. I've put some wear and tear on this trying to de-pin it. It isn't cooperating. That second picture couldn't be more vague. Not stoked about splicing a brand new harness

Mike L.

8/8/2023

@JeremyC Sorry the page was lacking. I'll get with our video folks to get a video once we get that particular vehicle through our facility.

Pete G.

8/9/2021

Looks & sounds easy but a video would be a great help. Trying to follow instructions, I may have destroyed a connector since the wire came out but the crimp connector is still inside the housing.

Klaus W.

5/1/2021

I have a 2018 Frontier and I have purchased the appropriate Curt harness and controller. My problem is that my brakes lock up (with or without the controller). I checked the outputs to the Aux (black wire) and the trailer brake (blue wire). The are both hot, so it is not a switched wire scenario. The trailer brakes release when I disconnect the brown relay. Checking input to the relay, there is constant current to the coil, activating the trailer brake circuit. Any thoughts on the cause of this and a rewire solution. As a note, all other functions work perfectly.

Jon G.

5/3/2021

That honestly sounds like something going on with the OEM wiring and you'd want to get it checked out. The only thing that would make sense for the aftermarket wiring to be an issue is if something was mis-wired inside that harness.