I have a 91' Firebird, V6, and the AC vents do not work most of the time when I switch them on. They will turn on when I hit a bump, but when I turn the car on and off afterwards, it does not blow out air again.

I know next to nothing about where things are located around the engine, so keep it simple for me, please.

 

First welcome to the site.The controls for your HVAC vents are vaccuum operated.It uses engine vaccuum to move flapper doors behind the dash to direct air thru the defrost,dash vents or to the floor.A loose vaccuum line or bad control unit(the controls that you operate)will cause the doors not to open.
But from the description of your problem it sounds like you have a loose electrical connection either on the control unit or at the blower motor.The blower motor for the whole system is located under the hood on the passenger side of the firewall.If you turn the igniton on,but with the motor not running,turn the A/C control on.The blower motor should come on.Open the hood and go to the passenger side you'll hear the blower motor running.That's the easiest way to find the location of the blower motor(I'm sorry i don't have a picture).You'll notice a single wire going to the blower motor.make sure it's not loose.Try this and come back and post what you find.There's always someone better at explaining than me.I'm better at showing someone than trying to explain it.
The best suggestion I can give you is to get a Haynes or Chilton's service manual for your Firebird.This will help you locate the different parts to your car

 

Thanks for your help, I will take a look at it tomorrow after work, and post what I find.

 

This link may help:

https://www.thirdgen.org/forums/cool...er-heater.html

JamesC

 

Ok, so I went out there and tried that out, but when I switch on the AC, the motor doesnt even turn on. I checked the wires I could see, and they look alright.

 

https://www.thirdgen.org/forums/elec...ower-test.html

JamesC

 

Ok, the motor does turn on when I hit a bump...other than that, I dont know how to test the wiring like in the link you put in there. Sorry I am not very good with this stuff.

 

Thank you JamesC those links are perfect.Choas you've identified the root cause of you problem.Troubleshooting is the best way to find a problem instead of just throwing parts at it till it works.The motor brushes that conduct current to the armature in the motor are worn out that's why it works intermittently.Now you can go to just about any parts store(Auto Zone,NAPA,Advance etc.)and tell them the standard info for your car and that you need the blower motor for your HVAC system.The reason I say to specify is you don't want them to hand you the motor for the radiator fan(s).

And there's now reason to apologize you won't learn unless you ask.All of us have been in that position at one time or another.And that's why I suggested getting a service manual for your Firebird.Read/look through it to aquaint yourself with parts locations,service procedures/schedules etc.You can pick that up at a parts store too.

 

Alrighty, thanks very much guys, I will go get the part soon.