P3 Brake Controller in 2009 Chevy Suburban Suddenly Stopped Recognizing Trailer

Question:

Ok, I have a 2009 suburban Z71 TV using a Prodigy 3 P3 controller less than a year old towing a 1976 Airstream AS. On the first leg of the trip and towing prior to leaving everything worked perfectly. On the second part however, the P3 would not recognize the AS. I have tested the 7-pin on the TV and receive 14+ volts when brakes are applied and when the P3 lever is used. I have tested both ends of the umbilical cord UC and found normal ohms. I have tested the brakes at the brake wires of each brake unit both at 4.5 amps each when the UC is plugged to the TV and the AS and the 7-pin connection on the AS receiving 9amps in return loop when unplugged. When the AS is plugged into the TV everything else works- lights, signals, jack, etc... I have cleaned all connectors with CRC Electric cleaner, used an Emory board to brush all reachable connector pins. I have taken apart the AS side of the UC and checked all connections and did not see any corrosion or hot spots, the TV side of the UC is not serviceable. I have also checked all fuses on the TV and AS. So, I can figure: The TV is receiving power to the P3 and the UC The TV 7-pin is working The UC is working sending power to the AS The AS brakes are receiving power from the TV The AS has a complete loop from the 7-pin to brakes and back I have not checked the magnets on the brakes. My next step is to use a small amount of dielectric grease on the AS side of the UC to ensure good contact. What possibly am I missing? Thank you in advance

asked by: Douglas R

Expert Reply:

It is very possible that the brake magnets or the wiring to them are the problem. If the magnet wires are getting 12-13 volts on their power wires then make sure the ground wires are attached to clean and corrosion free bare metal surfaces. Inspect the magnets as well and if you can see the copper windings coming through then they will need to be replaced. I have included a help article on how you can further test brake magnets.

If the trailer has a break away system then you will need to also check that wiring as well as the charge on the battery. Since the brake output signal would go through a break away system on its way to the trailer brakes a problem with its wiring could also cause problems.

expert reply by: Michael H