Range Rover Headlights Cause Prodigy RF Brake Controller to Activate Trailer Brakes

Question:

I paired the Prodigy RF to my new Airstream and 2007 Range Rover HSE. I have mostly been driving around during the day and it looks like it is working well. I have automatic lights and when they turned on at dusk, the brakes were triggered! I noticed the display on the handheld controller went from .c. to 2.0. When I set the controller I set it on 11.0 and boost 2. The next day during the day I took the trailer for a test drive and again everything looked fine. I manually turned on the headlights and the brakes triggered again. The controller showed approximately 2.0 again and I could definitely feel the trailer dragging. I tried to lower the gain on the controller to a point where the brakes were still effective but that they wouldnt trigger when the lights came on. I couldnt find this middle ground. I didnt try to turn the boost down yet. Any other ideas on how to make this work? Id like to know Im not dragging the trailer when the lights come on sometimes during rainstorms the lights come on during the day and Id like to not have to adjust the controller for daytime vs. nighttime.

asked by: Andy D

Expert Reply:

It sounds like the brake light circuits on the vehicle side trailer connector get power when the headlights are on, or it could also be a short due to corrosion or wiring in the trailer connector.

First make sure the trailer connector is clean and free of corrosion inside and out.

To test the connector to see if there is power on the brake light circuits when the head lights are on you will need a circuit tester such as # PTW2993.

Test the pins in the 3 o'clock and 9 o'clock positions while someone sits in the vehicle and turns the head lights on and off. If those pins show power when the head lights are on, then that is likely the issue. There is no fix for this other than to install an in-cab brake controller such as the P2, # 90885, using wiring harness # 3035-P.

expert reply by: Michael H