P2 Brake Controller Blowing Fuses After Dealer Installed it in a 2018 Jeep Wrangler Unlimited (JK)

Question:

i just purchased a new 2018 Jeep Wrangler JK unlimited. I unplugged and removed my P2 from my 2010 and the dealer installed it to the 2018. now it blows fuses. the dealer insists that the P2 is bad. ..... I will be taking the jeep and controller to camperland where the P2 was originally purchased and installed to make sure it is bad ..... do you have any suggestions. and do you have the correct wiring diagram for the JK?

asked by: Gary

Helpful Expert Reply:

If I had to guess as to what happened I would say that they connected the P2 brake controller # 90885 red wire to the wrong wire on your 2018 Jeep Wrangler Unlimited (JK). It is a difficult wire to get to for sure on most Wranglers. They may have used a different wire that carried more than just the brake light signal thus causing an overload condition.

Take a look at the video I have linked showing installation of a brake controller on a Jeep just like yours. The controller is different but the connections between the Jeep and the controller will be the same.

For a brake controller the white wire is the ground and if hardwired to a vehicle should go to the negative battery terminal only. Black is power in from the battery. Blue is output to electric trailer brakes. And red is input from the brake switch. If they swapped the power and ground that would destroy the controller. If it was a short on the blue wire the controller would show an error code (SH or OL).

expert reply by: Michael H