Troubleshooting Primus IQ Brake Controller That Shows Connection But Doesn't Work with Pedal

Question:

My Primus iq is connected and reads the .c. But it does not apply the trailer brakes when stopping I can apply them manually but it will not apply by itself The photo is a item camper world added when I installed

asked by: John V

Expert Reply:

The issue is the red wire of the brake controller. It needs to be connected to a circuit that only sees voltage when the brakes are applied. It sounds like yours isn't connected anymore or on some vehicles the issue is that there is a blown third brake light fuse. This is especially true if the vehicle is a GM truck.

expert reply by: Jameson C