View Full Version : trailer reverse lock-up

04-29-2009, 12:38 AM
my tahoe burns up trailer b/u fuse every time i try to back up and then the trailer locks up. i've had two places fix the trailer and i have no idea how to fix this. any suggestions?

04-29-2009, 01:13 AM
the trailer locks up b/c when you fuse blows, there is no signal going to the trailer. the reason the fuse is blowing is probably due to a short on that wire that goes to your trailer. Do you have back up lights on trailer? If you do, that could be where the problem is, or it's where your wire that goes to the brake actuator when you're in reverse on your trailer.

04-29-2009, 01:37 AM
thanks, i'll check it out.

04-29-2009, 03:51 AM
Check your ground wire at the trailer and also at the truck.

05-13-2009, 07:03 PM
Assuming you have a 5 flat harness which means you have a reverse lockout solenoid? If you do and it only blows the fuse in reverse you need to check for a short in your solenoid wire or the solenoid itself.

Once the fuse blows the solenoid releases and the brakes lock, especially with disc brakes.

05-14-2009, 11:25 AM
I have never had the fuse blow, but I have had a short that prevented the solenoid from engaging. It took a little while to find it, but one I did it was fine. I assume that they are the surge brakes, if so, one thing I learned was to carry a nut that was the size of the slot in the side of the trailer tongue where the two parts of the trailer tongue slide back and forth to actuate the brakes. By putting the nut in the slot it stops the brakes from being actuated without the use of the solenoid so you can still back the trailer up without locking the wheels. That way if I had a problem I could still use the trailer until I got it home.

05-15-2009, 12:50 AM
thanks for the advice, it is a blown tr. brk. fuse in my tahoe. it's blowing every time i get it backing up on a upward slope. just need to fix the short now. i use a screwdriver when it locks like that. seems to work, but only temporary fix. new to the forum, so thanks for the advice.

05-15-2009, 01:20 AM
I have had the same problem, after taking apart the brake acutuator, I noticed the reverse back up wire going to the top of the back up solenoid had rubbed against the trailer frame and rubbed all the wire housing off causing it to short onto the trailer frame. I took a bunch of tape and wrapped it up but I will need to replace the solenoid since it is connected currently with like two strands of the wire. I got a replacement but need to remove it but I am not looking forward to bleeding the lines. What is the easiest way to bleed the lines without the special bleeding tanks?
good luck in finding the short.

jamica joe
05-15-2009, 08:20 AM
My tahoe was having similar problems... I ended up taking the round harness connector apart. There was a tab that had been folded down and was not connecting correctly (from the Chevy factory). It too about 5 min. to fix. No more locking up / blowing fuses

05-17-2009, 08:48 PM
It's fairly simple to bleed the brake lines once you've replaced the solenoid. You'll need extra DOT 3 brake fluid, a glass jar, and a clear hose that fits the bleed ports on your wheel.

You connect the hose to the port on the farther wheel from the master cylinder, open it by turning it counter clockwise, and place the end of hose in the glass jar with enough brake fluid to keep the end of the hose always submerged. Fill the master cylinder and cycle it (per your model's manual) until there are no air bubbles coming out. Close the port and connect the hose to the next wheel and repeat.

NEVER REUSE THE BRAKE FLUID. Also be careful with plastic containers since some are readily soluble in brake fluid.