1978 Ambassador - brakes locking on

[pemmy]

Hi All - relative newbie here. Wife and I (on somewhat of a whim) bought a 1978 28ft Ambassador and are quickly trying to make ourself experts in all things towing.

Having an issue at the moment with the brakes locking on. TV is a 2011 F150 with the integrated trailer brake. Gain is set to zero. The slightest touch of the brakes results in them locking up. As soon as the brake is released, the trailer brakes also release. As a result, we have barely taken the AS out of the drive.

PO towed the vehicle to us about an hour and I drove with him for a bit and trailer brakes were working fine on his vehicle (late 90's silverado).

I do have a 7 pin to 7 blade adapter and lights generally look like they are working correct. PO vehicle was wired with same plug as trailer.

Any suggestions of what could be the issue? A short? Blown fuse? Wiring not actually connected correctly

Any help would be great. I did search the forums but couldn't find anything that looked similar.

[overlander63]

Welcome to the forums.
It sounds like the brake power is wired to one of the turn signal outputs. As soon as the brake lights come on, the trailer brakes would engage fully.