clearly it's a diverter control that's blocked or a vacuum line has cracked or fallen off....see if you can get an eyeball on the mechanism...you may have to disassemble the dash a bit~....wow you've got separate motors for left and right~!
looks like one of your cooling fan relays is burnt~ swap 'em out (if identical)~
Follow "Judge Roy's" answer, Ford Rangers have had the same problems for years.
it's true Fordtudor37...a unique arrangement...looked to be three relays one for two and one for each...why they did this? god only knows...but if this schematic is correct she does not need to look for anything other than the relays and the cause of the relay failure~
Looking for a Used Grand Prix in your area?
CarGurus has 2,552 nationwide Grand Prix listings starting at $1,750.
Search Pontiac Grand Prix Questions
Pontiac Grand Prix Experts
Related Models For Sale