Troubleshooting P3 Brake Controller When Brakes Only Work With Manual Override

Updated 05/28/2015 | Published 05/26/2015

Products Featured in This Question

Digital Multimeter with 42" Long Test Leads - LED Display

(3)

$21.87

Question:

Hello: I have a Tekonsha P3 brake controller that I used successfully in my 2004 Toyota 4Runner for the last 2 years, I recently changed the TV to a 2006 Nissan Armada with a tow package and had to purchase a new wiring harness to match the Nissan plug-in connector. I made the brake controller install along with the new connector, however I hade no trailer brakes when I depressed the TV brake when I went camping this week. Only the manual braking on the controller worked. Can you assist me in troubleshooting? Should I start with switching the new Nissan wiring Part #3050 harness? PS: What is weird is that on my return trip it started work I reseated the connections on both ends of the harness while camping. But at this point my confidence level is low. Thank you:

asked by: Garfield B

Expert Reply:

I have attached a couple helpful articles that explain how to troubleshoot your brake controller installed on your Armada. Typically, when the brake controller only works with the manual override, the problem is with the red stop light wire. That is the wire that sends the signal to the controller when the brake pedal is pressed.

You may want to check the owner's manual and locate the CHMSL fuse and check to make sure it is not blown. You may want to make sure the power settings on the brake controller have not been turned down too low, which would be a very simple fix.

There should only be power on the blue wire at the back of the controller when the manual override lever is pressed. If it shows power at any other time that does indicate a problem. The black wire should have 12-volt power into the brake controller. You can try splicing the blue wire directly to the red/green wire going into the vehicle side connector. You will want to use a circuit tester like part # PTW2993 to make sure the red/green wire works every time the brake controller is pressed first.

The red wire should have power on it only when you step on the brake pedal, and the White is ground.

expert reply by: Jeffrey L