With you asking it just reminded me of how long it had been since i was at the dealership. so here i am with my manual and if you take off the kick panel on the passenger side you will see the blower motor assembly. the auxilary one is in the centre console just before the back seating area. these things are real easy. just keep track of the screws lol. if its making noise it will need to be replaced but pull it first to make sure there are no leaves in the housing. be sure to double check the numbers for the gm number. these are ACME units and if i remember right you can get a gm aftermarket replacement cheaper then HUMMER.