My 2001 Pontiac Grand Am has a grinding noise coming from the AC/Heater. The ac still works but the noice is awful.

SOURCE: heater and ac blower

I have an '04 with approx. 79000 miles; the blower is going out on mine too. The motor is probably burned out and you will need to replace it. It's about $90 for the part. Kind of a pain to change; I changed the blower motor on my 97 'prix and I had to lay upside down on the passenger seat and work on it upside down. Other than a little physically uncomforable, not too hard to do.

SOURCE: exhaust fumes coming through heater vents

YOU HAVE AN EXHAUST LEAK ON THE FRONT END OF THE EXHAUST SYSTEM.GET THAT FIXED ASAP! THAT IS CARBON MONOXIDE!

SOURCE: Replace heater core in Pontiac Grand Am GT 3.4l

ram a sharp chissel or pointed head centre punch through the core and prise it out .,than tap the new one in place ,,,there u go bobs ure uncle

SOURCE: the blower fan speed control stopped working

usually a bad blower resistor is at fault...

SOURCE: grand prix 3800 blowing only hot air please help

check the temp control switch in the dash