It was not performing properly.... so it needed replaced. 4x4 lights went crazy and DIC malfunction flashed. So, if T-lights Christmas tree on your dash... and buttons are not sticking in mid-position... and all else fails to solve; then consider circuit malfunction bulletin #09-04-21-005B

also, it happened during really wet weather

 

For the record, my T is running great and could not be more happy. Great truck and great dealer service too.