Troubleshooting Prodigy P3 No Trailer Connected Error

Updated 09/21/2024 | Published 09/20/2023

Products Featured in This Question

Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional

(6644)

$156.06

10 Gauge Wire - Blue Primary - Per Foot

(104)

$1.84

Hook Probe Circuit Tester

(60)

$12.41

Question:

When we hooked race car trailer to mh brake box says not hooked the trailer and all lights work and turn signals and emergency lights brake controller is a prodigy 3

asked by: Marvin S

Expert Reply:

The brake circuit of the Tekonsha Prodigy P3 # 90195 is on a different circuit than the lights for your trailer which is why everything else it working great but the controller is having issues.

Since your note is saying that the trailer isn't connected you need to check the blue wire from the controller to make sure it's running without any issues to the back of your motorhome. You likely have this wire damaged, pinched, or exposed somewhere which is causing a misreading. If you can't visually find anything wrong you'll need to use a circuit tester # PTW2993 to see where the voltage drops when you send back power with the manual override. Start about 6" back from the controller and work your way to the 7-Way for testing with the circuit tester.

If all of that looks good then the issue could be on your trailer brake circuit instead so you'll need to do the same thing on your trailer.

Worst case scenario is you run new 10 Gauge Wire # 10-1-1 from the P3 back to your 7-Way., or from your trailer 7-Way to the trailer brakes depending on which side of your towing rig the issue is on.

expert reply by: Jon G

Rik H.

9/21/2024

Quicker way to locate problem is to start in middle of wire and go toward controller if low if ok go toward trailer. then keep measuring at half way points of remaining wire until you locate problem. By doing it this way you eliminate half the remaining wire length at each test point.