I have a 2000 Pontiac Grand Prix. I'm having problems with the heater, First off i replaced the Blower and the resistor as the previous one was fried. it never worked on 1 > 4 just 5. than one day that quit. and now after replacing all that it only turns on at 5 but doesn't blow any heat/cold air. just makes a buzzing noise. im just confused now as to what it could be. also checked the fuses, but, that was just the hvac hi 30 amp fuse.