Troubleshooting No Trailer Connected Code on Tekonsha Prodigy P3 Brake Controller

Updated 05/08/2024 | Published 05/06/2024

Question:

In short : Tekonsha P3 flashing red, showing no trailer connected when hooked to trailer. Truck - 2001 Ram 2500 5.9 Cummins, factory wiring harness and 7 pin. This is a new brake controller. I had the Tekonsha voyager for many years with flawless use. The indicator light on the voyager went out so I decided it was time to upgrade to the P3. I am a contractor and tow trailers daily. I purchased the P3 and factory harness for plug and play install. The trailer/s lights turn on and function as normal, but the P3 does not recognize a trailer being plugged in and brakes do not engage with the peddle or manual lever. I am fairly confident the issue is within the truck as I have 4 trailers 3 electric brakes, 1 hydraulic over electric that I plugged into all with the same diagnosis. P3 troubleshooting menu: Battery voltage- 14.4 Stoplight- 12.8 peddle depressed 14.3 manual lever Output voltage- 2.1 peddle, 12.6 manual lever Output current- 0.0 amps peddle, 0.1 lever I also checked voltage at the 7 pin. There was some light corrosion which was remedied with CRC QD electronic cleaner. Using the ground pin as a ground I received 12.8 volts at the brake pin blue wire. I am familiar with the P3 units as I have had them previously on several of my other work trucks with no issues. However I am thoroughly stumped as to why I am having these issues. Please help Thank you in advance!

asked by: Geoffrey B

Expert Reply:

Thanks for reaching out about the Tekonsha Prodigy P3 # 90195, Geoffrey!

Since you've connected a few different trailers I do agree that the issue is likely on your 2001 Ram 2500 side of things.

What you'll need to check is the output wire from the controller. This will be the blue wire coming out the back and it will run all the way to the pin in the 5 o'clock position (see attached). This is the circuit that detects if a trailer is connected or not so if the wiring here or even inside the 7-Way is broken or damaged somehow then that would be throwing the code.

It is possible that the P3 is defective, but these controllers are some of the most reliable on the market so defective ones are few and far between.

expert reply by: Jon G

Output Pin on Vehicle Side 7-Way
(click to enlarge)

Geoffrey

5/7/2024

Jon thank you for your reply. As mentioned above/previously I did check the output wire at the 7 way and it measures 12.8 volts. Any other suggestions? Thank you in advance

Jon G.

5/8/2024

@Geoffrey I would still check the wiring behind the 7-Way and inside the socket. It could be that your tester isn't pressing on the pin enough to throw the code, but once you push the trailer 7-Way into the socket that causes the wiring to get messed up.