Troubleshooting Trailer Marker Light Illuminating When Brake Controller Manual Override is Used

Question:

when i manally apply the brakes the marker lights all come on is this normal. my primus iq brake controler

asked by: Scott E

Expert Reply:

When using the manual override brakes on your Primus IQ # TK90160 the marker lights should not come on. The brake lights should come on to let the people behind you know the brakes are being applied, but the clearance marker lights should not. It sounds like you have either a crossed circuit in your trailer wiring or there is corrosion that may be causing the pin from your brake controller output to power the ground on your trailer. If you are adding power to your frame that is an issue you will want to immediately remedy. I recommend cleaning the trailer connections on the vehicle side and trailer side using some sand paper and then some dielectric grease # 11755 to prevent future corrosion.

If this doesn't solve your issue, then I recommend going through each function using a circuit tester like # PTW2993 to determine how that power is being added to that circuit.

expert reply by: Jason S