Troubleshooting Low Voltage at Brake Assemblies with Prodigy P3 Brake Controller

Question:

Purchased new P3 controller with harness for factory wiring on 2018 Ram. Getting 12 volts to trailer side of 7 pin connector. Only getting 9.7 volts to brake magnets. Boost option is not on. Trailer is a new tandem axle with brakes to all wheels. Have not been able to adjust controller to lock up for new install. Please advise. Thanks,

asked by: ROBERT K

Expert Reply:

If you have set the Prodigy P3 # 90195 all the way up to 12 and your trailer brakes still aren't locking up during the initial testing (while driving around and using the manual override), then I think your issue might be that your wiring gauge is too small on your trailer. We recommend at least 10 gauge wire # 10-1-1 because that should be big enough to get enough power to your trailer brakes.

Typically if the brakes weren't locking up I would say to adjust your brakes, but since this is a low voltage situation I would check your wiring to make sure it's big enough. It would also be beneficial to check the grounds for your brake magnets and possibly run them up to the main ground on your trailer to make sure there aren't any issues with the brake line circuit.

expert reply by: Jon G