Re: Trailer brakes locked up
You apparently have a surge brake system that does not have "free backing" brakes. This means you need to look at the coupler for a lockout device that locks out the brakes when backing up. Surge brakes operate on the principle that when the tow vehicle is braking, the force of the trailer against the tow vehicle actuates a master cylinder just as you do when you step on the brakes. The more forceful the stop is, the harder the trailer brakes apply. Therefore, backing up has the same action and the brakes apply. Going downhil would not pose much of a problem but backing uphill into a driveway causes the brakes to actuate.
There is another way to do lock out the brakes automatically. Installing a lockout solenoid in the hydraulic system allows the solenoid to activate when the tow vehicle is shifted into reverse. This releases hydraulic pressure so you can back up. This requires another wire in the electrical harness between the trailer and tow vehicle. It gets connected to the back up light circuit.
