If you've followed the installation and troubleshooting instructions carefully and the unit isn't functioning correctly, then call MaxBrake for support at 337-542-4050.I have hooked trailer up did the calibration, drove on the freeway trailer stop smooth first time, then the display went blank, truck engine running nothing showing. Drove several miles no trailer brakes, I plugged in my Old Prodigy unit and was working just find. Is this normal that the display goes off? No brakes I think not. #@$%!