Trailer problem

I have an Extreme tandem trailer. Recently I broke the safety cable. I had to take the brake assembly apart to replace the cable. I got everything back together and thought all was good. It turns out when I go to reverse, it locks up the brakes. This happens immediately when the boat is off the trailer. When the boat is on the trailer, if I back up slowly I can go in reverse without the brakes locking up. But when there's a little hill or when backing into my driveway (slight incline) it locks the brakes up.
Does anyone have any idea what the problem might be?
Thanks in advance.

Sounds like you didnt hook up the circuit for the reverse lockup solenoid back correctly. Either that or you have blown the fuse for the backup lamp circuit.

(Message edited by jimmy_z on August 17, 2009)

I just replaced my backup solenoid because of the same issue. The problem was the tow package fuse. I thought all was OK because the reverse lights on the truck were working but its a different fuse. If you replaced the solenoid make sure to bleed all of the brakes.

It turned out to be a bad connection. I rewired the harness with watertight connectors and heat shrink wrap. It's working great now.
Thank you Jim and Bryan for the responses.