Ok. You all have schooled me on my options for the retarder activating the brake controller for my cargo trailer breaks. I don't want to cut the wires at this time and my local shop doesn't understand retarders enough to place the diodes so for now I'm thinking just back the brake controller off to a minimum power setting to save my trailer brakes. It's a Prodigy.
What do you think? I believe it's my only option for now
Thanks
I added a trailer specific air brake switch. It wasn't too hard to do and now my trailer brakes only come on with the brake being applied.