yes could be a control unit issue with the DCM. i dont belive there
is a relay for that. thats what the DCM is for. Im all out of suggestions for you. maybe someone else on here has an idea as to what the issue could be. sounds like you need the dealership now. a diagnostic test couldnarrow down the culprittothe problem.
good luck!

 

Your help was much appreciated. I, too, see a dealership in my future...