It seems like there must be a fuse on this, but I don't see one mentioned on any of the fuse covers or in the manual.
I managed to knock the cover off the unit in the trunk-- and then to turn a corner just right so a can of soda exploded on the exposed sharp metal pieces. Soon after I noticed I didn't have Onstar.
I'd like to replace the fuse first before I take it to the dealer for an assessment.
Thanks, Jim