P3 Brake Controller is Not Recognizing that a Trailer is Connected to 2016 Nissan NV 3500

Question:

So I recently bought this set up for my Nissan nv 3500 the controller reads every time I hook up trailer that there is no trailer the trailer is good and my 7 pin connector is as well what could the issue be

asked by: Mike

Expert Reply:

There are some things you can check on the 2016 Nissan NV 3500 and P3 brake controller # 90195 to determine what the problem is. First, make sure the trailer is NOT connected to the NV. Next, you will need a circuit tester such as # PTW2992 or a meter if you have one.

First, set the brake controller to the maximum output level. Then have someone sit in the vehicle and operate the manual override lever on full while you test the pin in the 5 o'clock position in the 7-Way connector. It should have power when the manual override is on and no power when it is off. If it has power all the time, then perform the same test only at the pin in the 1 o'clock position.

If the power goes off and on when the manual override is off/on, then the issue is that the 12-volt circuit and the brake output circuit are switched. The easy way to fix this is go to the back of the 7-Way and switch the wires at those 2 locations.

If it does check out fine on the vehicle side, then the issue could be on the trailer. Looking at the face of the trailer's 7-Way the brake output pin is in the 7 o'clock position. Make sure the wire associated with that pin goes to the trailer brake magnets. If it does not find the wire that does and attach it to the proper location on the trailer's 7-Way.

If you test the vehicle side and do not get any power when the manual override is used, then it is possible that the blue output wire is not ran from the front of the NV all the way to the back. You could bypass any factory wiring by connecting a wire to the blue wire coming out of the controller, running it through the firewall, down under the vehicle, and back to the 7-Way and attach it in the 7 o'clock position at the back of the 7-Way.

I have included some additional links below on testing and troubleshooting brake controllers for you.