Gill was very helpful in this matter. But before I got back to the truck a second mechanic removed the harness from the control unit and replaced it with a cut off serial cable. The unit now keeps the release solenoid energized. I kindly saw my way out of the loop as it is difficult enough to trouble shoot a single problem let alone one that was created by a different set of hands. Noise was suspected to be in control panel. That is where an am radio picked up static. Not a highly scientific way to locate it but at the suggestion of a fellow tech.