Troubleshooting Tekonsha Prodigy P3 Not Working When Truck is Turned On
Updated 10/30/2025 | Published 02/16/2025
Question:
I am having an issue with the controller saying no trailer connected and I get no trailer breaks when the truck is on. When the truck is off it shows connected and will apply the breaks on the trailer. It was working fine the day it was installed but the next morning it started doing the above. Is there something to remedy this?
asked by: Ray
(click to enlarge)
(click to enlarge)
Expert Reply:
Hey Ray! That is certainly unusual behavior. Since the Prodigy P3 # 90195 shows it is not connected when the truck is on I would start by checking the vehicle side connector. It sounds like there could be some corrosion causing the issue. I'm not sure how the 7-way functions on your truck but if you don't have power to other functions when the truck is off and do when it is on I could see that causing a problem if power carries over through corrosion.
The other thing I would be looking for is a bad ground. Start by double checking the P3 and then double check your other ground connections to see what you find. They should all be secure on a clean, bare metal surface. It wouldn't hurt to check the trailer connector for debris or corrosion as well just to be sure.
Product Page this Question was Asked From
Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional
- Trailer Brake Controller
- Proportional Controller
- Electric
- Electric over Hydraulic
- Splice-In
- Under-Dash Box
- Under-Dash
- Up to 4 Axles
- LCD Display
- Multiple Trailers
- Tekonsha
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Shop: Replacement Trailer Spindle Jam Nut - 1" Diameter - Plain
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Article: Brake Controller Installation: Starting from Scratch
- Q&A: What is the Difference Between the Tekonsha Prodigy P2 and the P3 Brake Controllers
- Article: Trailer Wiring Diagrams
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Q&A: What is the Difference Between a 4-Way and 7-Way Trailer Connector
- Article: Towing a Trailer? Let's Talk About Brake Controllers
- Article: Installing an Electric Brake Controller on 2007-2013 GM Full-Size Truck or 2007-Present GM SUV
- Article: Aftermarket Brake Control Wiring for 07-13 GM Full-Size Truck with Factory-Integrated Brake Control
- Q&A: Brake Controller Wiring for Ford E-450 Motorhome
- Q&A: Brake Controller Recommendation for a Truck with Air Brakes and a Trailer with Electric Brakes
- Q&A: Should I Get a Proportional or Time-Delayed Brake Controller
- Q&A: Is There Downside to Going with 7500 Air Lift Kit Over 5000
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
Robin H.
10/30/2025
Hey Ray, did checking the grounds and cleaning the connectors on your Prodigy P3 help get the trailer brakes working again? Knowing what fixed the “no trailer connected” message could really help others running into the same issue.