Have a 2006 myco Electric over hydraulic that when applied they wont release(created quite a smoke the other day lol). The only way for them to release was to undo the main brake line out of the actuator. All released and was fine except no brakes on way home. Once home redid all bearings and brakes (pads and calipers). All wiring is clean tight and connected. The only two things i have not done is the little black box that allows my truck (2011 gmc) to talk to trailer and the actuator. Would like other thoughts before replacing the expensive actuator. Ever happen to anyone else.
Thanks

Have you tried another truck just to be certain? The folks at Brake Right are very friendly. They should be willing to step though a few things with you.