towing my boat with our new 21 Disco and when I'm trying to go in reverse, my surge brakes are engaging. This wasn't happening with the previous vehicle (17 Lexus GX460).

The trailer manufacturer replied: The new vehicle may not have been properly wired for the reverse brake lock-out. Occasionally there is a fuse that needs to be installed in the vehicle fuse box that is not a standard feature (seems illogical but we see it all the time). You are welcome to drive the vehicle over and we can test it but we will not be able to fix it. Your best bet would be to contact the dealer and have them test the power coming out of the vehicle for the wiring harness.

Anyone experience similar?

 

I used to experience this with a Suburban. One simple concern would be that you are stopping first before you reverse....that will activate the brakes, then they don't release. For a test have you tried to stop very gradually, in an attempt to not activate the surge brakes and then try reversing gently?