Prodigy P3 - No Trailer Connection - SOLVED

After my last post I decided to dig further tonight. Low & behold the problem was caused by a corroded ground at the 7-pin connector. I pulled it apart cleaned it off & wallah it is working perfectly. Thanks to everyone for offering advice.

I spoke with tech support today. They wanted me to check the ohm resistance at the controllers connector between the blue & black wires while the trailer is connected. I did this & the reading stays all the way to the left. I then checked the 7 o'clock & 5 o'clock connectors on the trailer plug & the reading went all the way to 0 ohms.

I also checked the connections of the controller wiring harness to the truck wiring. All those connections are good.

I'm at a loss as to where to go now.

I dont own one but Id bet the Prodigy series will give the "No connection" msg when it cant sense current draw from the brake solenoids which I suspect is a test signal provided on an ongoing basis. That says check your blue wire to the connector/trailer plugs.

It wont be right/left turn - they are temp when turning.
It wont be Running/clearance lights as they are not always used.
I wouldnt think it would be the battery charging circuit as that may not exist on some trailers.
I dont think it would be the ground, but it could be.

It seems all that is left is the blue wire and a trickle signal is sent continuously to determine if the trailer is connected.

As RCMAN46 suggests you can quickly cut your effort in half by connecting another trailer or your trailer to another vehicle.

You may need to verify the wiring to each solenoid after checking the connectors.

There is a 95% chance you have a wiring problem. The 7 way is the place to start. After that if you have a friend that has a Prodigy controller trade trailers and see where the problem goes. Then you will know if it is in the trailer or the truck.

they never apply full power unless you use the manual slide or really jam the brakes.

Dirt or loose connection at the 7 way plug.