Just recently my trailer started locking up in reverse. It has never had this issue. Its go the 5 pin connection. Which pin engages the reverse to override the brakes? Is there a way to test where I am losing the connection? either at the harness in the truck or the trailer harness?
If you flip the plug 180 degrees and turn your lights on see if it still does it. If it doesn't lock up then you know it is a problem with the vehicle wiring. If it does lock up it is the trailer wiring.
I fought with the same problem. I ended up finding a troubleshooting post somewhere that said to use a battery and apply voltage directly to the solenoid. To test you can just jump power to the blue wire and touch the ground to the bottom of the solenoid. You should hear the solenoid click. If you do the solenoid is good. The solenoid gets its ground though where it attaches to the trailer but these get bad. There should be two small threaded holes in the bottom of the solenoid. Crimp a ring on a short piece of wire and attach with a machine screw. Don't remember the thread size and crimp to the white wire from your trailer harness. This should complete the ground.
Hope this makes sense. It worked for me.
More than likely he has surge breaks. The back-up light activates the hydraulic lock-out via an electric solenoid. However, any number of items can break to not allow the system to work correctly. Sometimes you might have to wait a few seconds for the solenoid to operate or you will get an initial brake pulse when starting to back. As you have heard, test the electrics first, then move to the hydraulics/brake system. The last pin activates the brake lock-out. It should have power when you select reverse. All of the systems have a mechanical lock-out device if needed.
I just got done being educated on this topic last week!
The back up brake pin is the one farthest from the open pin. Like suggested to me last week, if you have a swinging hitch, make sure the blue wire didn't get damaged.
I just had some one sit in the truck and put it into reverse and I was in back with a test light to check my connection. FYI: On my '11 Dodge, the center post on my truck's socket was the back up brake thingy.
Ya he is correct. The center is usually the reverse, take the plug apart, and be sure the wire from you solenoid(blue) is connected to your center plug pin. If the solenoid went out, you may have to replace it or the entire actuator(it was only 100 more for an entire actuator) Then you know you get all new parts, plus a new resivore and master cynlinder
whats more frustrating its been happening every time I go to reverse into my covered area at home. So I've been keeping a nut on a piece of tape to insert into the slide to keep it from going back all the way. Then, after I get some suggestions from you guys to check....yesterday it backs right up...go figure