E40D Electrical, Brakes and Brake Controller

[tuckerd1]

I have done the following over the last few weeks:
1. New Tekonsha P3 brake controller - 4 weeks ago
2. New in bed trailer connector - 4 weeks ago (old was corroded inside bad)
3. Hydroboost brakes with modified brake pedal 2 weeks ago

I am having a couple of problems with TQ lock/unlock and my Tekonsha P3 showing "No trailer brakes connected" and "Short in battery connection" while pulling the horse trailer.

The TQ will unlock/lock in drive (but not in OD) and the controller flashes one or the other errors. But the unlock/lock and the error messages do not occur at the exactly the same time.

Some more history:
4 weeks ago after the brake controller/trailer connector install I drove 700 mile with the trailer and had no problems.

Last weeked I pulled the trailer about 40 miles round trip and on the return leg these problems showed up. This was after the hydroboost install.

I know I need to check the trailer connector for shorts in it and possibly the controller for failure. What else would be good to check that may be causing the unlock/lock issues? Do you think these issues could be related? Could it be a brake switch issue where I modified the brake pedal?

 

[LCAM-01XA]

For some reason Ford connected the ECM to he return side of the tail light,s instead of the BOO switch, so if you have a burned out light, or a bad connection there, the TC will sometimes go stupid. Cat_Rebel just went through that when he installed his flat bed, he put LED lights on it and the TC completely refused to lock...

The P3 error messeges are connection related as well, I've had the "short to ground" show up too and that was after fording some rain waters that had turned M-24 into several small lakes, of course I realize the situation after I fly in it full speed ahead. When truck dried off all was good, I know where the water gets in to mess it all up and one of these days I'll go and fix it. Check your connectors in and under the bed where you're you've tapped into the bed harness. By the way, the P3 does not care if your trailer lights work, it only knows if you have connection problems in the electric brakes signal. How do you have it wired it under the dash, do you take the brake trigger signal from the BOO switch, or from the steering column harness like the install manual says?

 

[tuckerd1]

How do you have it wired it under the dash, do you take the brake trigger signal from the BOO switch, or from the steering column harness like the install manual says?

I have it plugged into the prewired plug under the dash. I haven't checked to see exactly how that is wired into the brake circuit.

 

[LCAM-01XA]

Ah, okay, I was asking out of curiosity, it don't make a difference for the issues you're experiencing either way.