Last year I installed my P3 controller to go with the new axle and new electric brakes. This year they have stopped working. When I connect the trailer to the TV, all the signals etc. work, but the controller says the trailer is not connected.

I'm not sure where to start looking for the problem. The TV has a 7 pin male connector, the cable has a 7 pin female on both ends and the the trailer has a 7 pin male to plug the cable into.

How would you troubleshoot this?
What sequence would you follow?

"Trailer connector disconnected or corroded." From:Tekonsha Website That's where I'd start... only because it's easy. Triple-check the connection to make sure it's tight. Test. Pull it out and scrub (green scratchy) the male pins, reconnect. Test. Dielectic grease (if the connection has ANY chance of having moisture inside) on the male pins, reconnect. Test.

That's my 2-1/2 cents beyond check the ground of course ;-)

Hi Roy,
I often find the contact surfaces on the seven pin plugs oxidize between uses and lights or brakes or both will not funtion until the plug has been inserted and removed a couple of times. Is there a fuse in the line supplying power to the controller? I have a flat 4 test plug with L.E.D's to indicate proper function of TV(bought at Princess Auto $4). I understand there is something similar for 7 pin but havn't seen one yet. If you have a means of testing the TV it eliminates 50% of your possibilities and you can then concentrate on the trailer. I have also found the 7 pin plug corroded from salt spray coming off the tires in winter. Dielectric grease inside the 7 pin can extend the life.
Bill

I had this problem during a trip home from Bandon a couple of years ago. It started out to be intermittent, a flashing of "n.c."

First I unplugged the Brake Controller from under the dash and brought it into Camping World who bench tested it for free, and found the unit to be working correctly. Then I got out my multimeter to run continuity tests along the cords and plugs that ran along the Blue Wire path from the Controller to the Brake Drums. I found a spot inside a cabinet under a bench inside the trailer where the Blue Wire had chaffed as the wiring bundle went thru a bushing, causing it to short to ground at that spot. I spliced in a new piece to replace the chaffed section, and re-routed the Blue Wire thru it's own bushing (not bundled with other wires) and the problem was solved.

I would take a circuit tester and test the blue wire to your Tug's plug and have someone push the brake pedal. If you have power there , then you know its in your trailer plug or wire back to the wheels.