Most likely you have bad power/ground to the trailer. Trailer ABS module communicate with truck thru power wire. Bad intermittent power wire connection will switch trailer ABS module to use stop light as a power and trailer ABS light will be on every time you apply brakes. If yo...
). First, you need to understand how these units work. What the manufacturers grandly call a "sensor" is actually nothing but a magnetically-operated switch. When the magnet gets close enough, the switch closes, making contact between the two wires in the cable. When the magnet is ...