Thermostat possibly stuck open or heater control valve broken. Now if you mean the blower motor has stopped working, check the fuse, blower motor itself, or the blower motor resistor pack.
The blower motor on all 70-81 Firebirds and T/As is located behind the passenger side fender. Complete pain to change. The best way is to pull the hood and the passenger side fender and inner fender well. Some people simply cut a hole in the inner fender well to get to the fan and heater core. Suggestion.....if you do either of these procedures, change out the heater core while you are in there. Save you from doing it again when it finally goes.
You have to remove the passenger front fender. The blower is located on the firewall inside the fender.
Under dash on passenger side
Remove the water supply lines to your 1985 Pontiac Trans Am heater core. Remove the heater core retaining bolts. The heater core will come out. Reverse the process to install your new heater core.
where is the heater motor located at
The blower rheostat on a 93 Pontiac Grand Am is located inside the engine bay, just to the right of the blower fan housing. It is almost directly behind the trans dipstick. It isn't that hard to replace.
Inside the front passenger side wheel well (with a flashlight, you can see it through the fender vent). You have to remove the fender to get access.
No you do not need to change the motor only the bellhousing will be different and also the peddle assembly to add the clutch pedal.
put in a thicker oil if its the motor but if its trans. change oil and change the seal on the peace that you remove to take the oil out.
Most likely heater / blower relay under hood, left side relay box marked HTR on lid, try tapping it, if not - remove relay, if motor stops running, you should have another relay in the box to substitute - as a test, if it works, replace relay. Other times a power board / variable speed resistor board can go bad and cause this issue - it will look like tin can when removed, but yours should have and "old school" blower motor resistor - it will look like stretched out springs, located under dash near gas pedal / trans tunnel in heater box. Two screws and a plug - not a big deal. the variable speed power board can keep the motor running, the old school style will not.
it is 3, one by the fire wall is hard to change you need to pick up the engine and trans. to change it.