[TAKPAK]

One thing should be noted here; when testing the trailer brakes by pulling the safety brake pin on the trailer, make sure you have the main trailer plug UNPLUGGED from the tow vehicle. If you don't, the "backfeed" from the trailer battery and brakes into the truck's system tends to "scramble" the controller computer. Found this out the hard way. Fortunately, it finally did reset itself, after turning the truck off and back on a couple of times. This is on the "built in" (factory controllers). Don't know about aftermarket.