I have used one of these for several years. No messing around with vehicle wiring, just plug into the trailer socket and the light bar plugs into a power point in the toad. LEDs use minimal power, I have never had a battery drain problem. Just rem...
If it's a PAC brake, a likely cause is lack of lubrication on the pivot. It's not difficult to remove the unit, and if it can be freed, great. I had to have the exhaust brake replaced on my motorhome shortly after I got it, and it wasn't hugely exp...