easy fix. replace the fan relay next to the heater motor. i would go out and get the part number but it is f---ing cold. mine did the same thing. only $7.00 for a new one from gm.
Well the cruise is vacuum operated, and can easily get poped off during boost, so start checking under the hood. As far as the blower, you can take the plug of the back of the switch and clean the contacts that sould get it working again.
