Hello. I've got a 2000 # Dexter axle with electric drum brakes on my teardrop. The brakes were working and being recognized by the P3 Tekonsha controller for most of my recent cross country trip. On the return trip, for some reason, the Tekonsha controller stopped recognizing the trailer. All the exterior lights on the trailer are working fine, so the problem seems isolated to the brakes. All fuses seem intact, the controller in the auto is illuminating and on, but shows the red "no trailer connected" warning even though the trailer is connected. I put a volt meter on the 7 pin connector on the tow vehicle and with the meter's ground on the 7 pin's ground and the positive probe on the brake contact and the car's brake applied I'm getting a reading of almost 5 volts. With the arm on the brake controller applied (which applies the brakes on the trailer without having to step on the car's brake pedal), I get a reading of 12 volts when the arm is fully engaged. So this is telling me the brake controller is working and applying voltage / current to the 7 pin connector (although I'm not sure why I'm only getting 5 volts when the brake pedal is applied..... should I be getting 12 volts, as is what the volt meter is showing when the controller's arm is engaged??).... so that's my first question.
So provided the controller is functioning properly as far back to the 7 pin connector on the tow vehicle, any thoughts on why the brakes on the trailer are not functioning. It's all pretty much brand new wiring that is sheathed in loom. I've inspected it and do not see any breaks in the wiring. I've tested the continuity from the 7 pin connector on the trailer's cable (where it plugs into the tow vehicle) back to the junction box... testing both the blue wire and the ground for continuity.... no issues there.
any thoughts where to check next? I'm a little stumped on this, any help would be appreciated.
Thanks
John