Driving a 2020 1500 Eco equipped w factory installed tow package (brake controller) and pulling a 2018 Airstream w electrical brakes and 7-pin plugin. Trailer brakes work fine during normal highway driving; however, once I transition to slower speeds (town driving) the trailer aggressively applies the trailer brakes regardless of gain setting (testing @ zero to 10); the more I drive slowly the more aggressive the brakes are applied to the point of locking/skidding. I pulled off the road, turned off the truck, and reset the system; same results once I started up and drove. Only time the brakes ceased to behave this way was after I unplugged the 7-pin plugin from the truck; the trailer brakes released. 7-pin plugin appears clean and damage-free. I called Airstream; they said it is the truck voltage setting. Pulled same Airstream recently w my Range Rover w a handheld trailer brake (cigarette plugin) and no issues. Any suggestions? Thank-you.