Infamous Black/Blue Wiring Mixup On The 2005-2013 Nissan Xterras

Published 07/27/2017

Products Featured in This Question

(66)

$14.40

Question:

Thanks for the info, Conner, I really appreciate the help. I finally got a chance to start checking things and found that the pin in the 5 o'clock position (brake) has no voltage on it at all at any time, BUT the pins in the 3 o'clock and 9 o'clock positions (turn) behave like you describe -- no voltage and then voltage when the brake controller manual override is pushed. And the rear lights on my vehicle come on when I push the override. Could it be the harness is not wired right? All I did was install it and the relay harness as per instructions and no modifications were made to anything in the package. Should I open it up and look, or can you send a replacement and we try that? Please let me know what the next step should be.

asked by: Dennis T

Expert Reply:

Chances are that if the brake controller is reading the trailer while connected, then it is not a blue/black wire mix-up. To test this, you will need to use a circuit tester like part # PTW2993 and probe the 5 o'clock position on the rear of the 7-way. If the power is constantly hot, the wires are switched. If the 5-o'clock position is only hot while the manual override is activated, the wires are not switched.

If the wires are switched, you have two options. The first option would be to use a wire disconnect tool to remove the wires from the back of the connector and switch them accordingly. The other option you have is cutting the two wires back about 2-3" from the plug and reconnecting the black to the blue and the blue to the black wire. Once done, your brake controller should begin to function properly. I have attached a help article that will explain and guide you through this entire process.

If the wires are not switched, you will want to begin testing your brake magnets using the attached brake magnet testing article. You will then need to trace both wires coming from the trailer brakes for breaks or frays. Be sure that the ground wire is properly secured to a bare metal surface of the frame.

expert reply by: Conner L

Dennis

7/27/2017

Conner L.

7/27/2017

The pin in the 5 o'clock position which is for the brake signal should only receiver power while the brake pedal is pressed, or the manual override is activated. Splicing wires and making new connections will get very messy in this particular case as the wire functions could or could not have been reversed from the factory. The best way to solve this problem would entail cutting of the old 7-way trailer connector on the vehicle and start over, this time using a new one like the Hopkins Endurance Multi-Tow 7-, 5- and 4-Way Flat Trailer Connector part # HM48470. This connector has screw-in terminals on the back which will allow you to easily secure the new connections. To install this item, you will want to have a friend sit in the vehicle and perform each of the functions that are on the back of the vehicle's 7-way connector while you are underneath testing each of them with a circuit tester like part # PTW2993. The connector will come with an instruction manual that will show you which function goes to which port. I have also attached an installation video of the trailer connector for you review.