I have a 2007 Silverado with a 29070 3 port module for the Minute Mount 2 lights. None of the plow lights work with the plow connected. Checked all the fuses - good. Took the covers off the plow lights - verified grounds are good to plow lights by connecting test light to battery (+) and backprobing grounds on plow lights - they all lit. Connected test light to good ground and tried backprobing the pins on Port A connector - nothing happens on any pin. Does this indicate the isolation module is bad - anything else I should check?