Not sure what happen to the reply I posted this morning through the iphone APP but it isn't showing up so I will repeat it....T
Guys,
The truck is fixed as of late yesterday. Turned out to be a problem with the UBEC (underhood bus electrical center/controller...black box underhood, driver side containing relays and fuses). Dealer service department had never experienced this but when they couldn't figure out the problem they contacted GM who advised them how to check out the UBEC and it turned out to have an issue. They replaced it and it appears to have fixed the problem. Total charge was $940 of which about $280 was the UBEC part and there was a few other minor miscellaneous parts too. They waived several hours of their labor time and billed me 5.5 hours at $110/hr. Overall took longer than I hoped but was sure glad to find out it was nothing more serious.