Brake locked -electrical?

[Yukon Don]

I have what appears to be a brake engaging when I plug the trailer wiring harness into the receptacle on the truck.
I found it ran fine if I unplugged the thing (although the authorities take a dim view of running that way).

It's just the one side (right). I was always under the impression that power for the trailer's brakes comes from the trailer battery and only engages when the breakaway switch is pulled.

If it makes a difference, I just switched vehicles -now driving a 2013 Nissan Frontier.

Has anyone ever had this sort of situation before?

[caper]

You should have the 7 way plug on the TV checked. For some reason you are getting power to engage the brakes. Only one side might be engaging because is your TT is wired like our use to be. FR ran the brake wires to one side of the TT so the brakes were getting 100% power then they jumped to the other side where the brakes were getting less power. Had to have a new harness built to that the brake wire ran down the center of the TT then the wires were split to the four brakes using same length wire. This might be why the right side is the only side that is locking up.

[Batts-toy]

Originally Posted by Yukon Don

I have what appears to be a brake engaging when I plug the trailer wiring harness into the receptacle on the truck.
I found it ran fine if I unplugged the thing (although the authorities take a dim view of running that way).

It's just the one side (right). I was always under the impression that power for the trailer's brakes comes from the trailer battery and only engages when the breakaway switch is pulled.

If it makes a difference, I just switched vehicles -now driving a 2013 Nissan Frontier.

Has anyone ever had this sort of situation before?

When braking your TV power is also sent to the TT brakes if you have a brake controller installed in your TV. The brake away switch on the trailer works off your TT battery and applies the TT brakes in the event of a brake away. You definitely need to get your wiring checked, another possibility is if you have a brake controller and it isn't adjusted correctly it can lock up your TT brakes.

[Yukon Don]

The T-10 is pretty light so my only trailer braking system (that I'm aware of) is the emergency break-away switch.

I take it I should be checking my truck receptacle for power on the slot for the brakes?

[raspivey]

That's where I'd start. Assuming you don't have a controller installed, you shouldn't have any power going to that pin. If you do, it's probably getting full power to the brakes with nothing to regulate it. If your brakes aren't adjusted properly also, it could be that both are trying to grab, but only one is (tighter than the other). While you're playing around with it, check that all of the lights work properly, wouldn't be the first time I've heard of a connector being wired incorrectly. If that happened, it could be sending tail light power to the brakes for instance.

[Yukon Don]

OK, thanks all.
That gives me a few ideas of where to start looking.

Man ...I'd like to get out at least once this year without having to abort for some reason or another...!

[elind]

Is your trailer battery dead? When it is plugged in to the TV does it then power up the dead battery and also power to the brakes with the E-brake set?

[Yukon Don]

Originally Posted by raspivey

...wouldn't be the first time I've heard of a connector being wired incorrectly.

Bingo.

After much perusal of wiring diagrams and a session with a multimeter, I find that I have constant power to the brakes but no power to the 12V charging pin. On a brand new dealer-installed harness

The receptacle is a sealed unit so I'm going to do something quick and nasty for now and try again with the T-10 (it is stored just outside of town) this afternoon. I'll try and have a go at adjusting the brakes as well.
If I'm not back here at 5 whining, then it worked and I'll be happily enroute to the mountains (as in Jasper, AB).

Thanks again all.