View Full Version : surge brake problem

04-14-2012, 05:10 PM
I need ideas for the surge brakes on my trailer (2008 MC stock trailer).

The surge brakes won't disengage when the truck is in reverse, so even on flat surfaces, I can't back up with the trailer. The reverse lights on the trailer do come on and I've fully tested the electrical connection at the car, so the trailer is getting the reverse signal. I just had the master cylinder replaced and the problem started immediately after that.

I know the obvious answer is taking the trailer back to the dealer for them to fix it. That's a bit of a pain, so I am hoping to find a simple solution I can do myself (and I am far from a mechanic. What other possible reasons could there be why the surge brakes won't disengage when the car is in reverse if the trailer is getting the proper electrical signal (as indicated by the reverse lights on the trailer correctly coming on)? Any ideas?

In the meantime, I'm having to insert a pin in the tongue to keep the surge brakes from engaging in reverse. It works, but is a bit of a pain in the butt.

04-14-2012, 06:50 PM
I hope the dealer reconnected the power to the reverse trailer solenoid? Did they re-install the reverse solenoid? You should be able to see it. It looks like this...


04-14-2012, 07:18 PM
I had the same issue on my trailer and it was a bad solenoid. You can test it pretty easily to see if that's the culprit.

04-14-2012, 09:17 PM
Bad solenoid or bad connection at the solenoid like the folks above stated .....

04-14-2012, 10:53 PM
This sounds like the right answer. Unfortunately it also sounds above my pay grade for repair... I'll take a quick look next time I grab my boat and see if there is just a loose wire, but most likely I'll just drag it back to the dealer that replaced the master cylinder and make them fix it.

Thanks for the info.

04-14-2012, 11:03 PM
Good Luck on the repair. Not a tough repair could be your maiden voyage into becoming a do it yourselfer...enoug info here to do most projects.

04-14-2012, 11:10 PM
The reverse solenoid is just behind the master cylinder with a single wire leading to it (on mine anyway). View from underneath the tongue. Check when in reverse you have 12v at the solenoid. I would just pierce the insulation with a light tester. I would put money on it the dealer connected it to the wrong wire or not at all. The solenoid is only screwed in and shouldn't be hard to replace if you have got current.