HI my camaro is a 91 rs with the 305 v8. at first the ac and heat worked really good. now when i turn the fan and change the differnt settings all i hear is the vacum hissing like it should. but it doesn't blow air. any suggestions on how i could fix this

 

First, check the fuse. Second, check for voltage at the blower motor. If you have voltage and it doesn't work it id probably a bad blower. If neither of these provide answers it is possibly the switch in the control unit.

 

The default setting is defrost. If air is blowing there but not through the other vents, then you have a vac leak. Stick your ear to the pass side of the HVAC control head. If you hear hissing there, the fault is probably the vac selector switch as bingo suggests.

JamesC

 

it happened to just be the fuse. but another question is it me or does your air seem to blow kinda week compared to other cars. like my mustang blows the air out alot faster then the camaro.

 

I have owned three F bodies and they all seemed to blow air weakly. I had several Fox body Mustangs and they would blow your hair back. I put a new blower in one of my Firebirds and it helped a little. Often times you can pull the blower motor out and clean out leaves and such and it will help.

 

ok this is getting annoying. i replace the fuse and yet again it blew it. this is going to be the third fuse now. Do you guys think i need a new unit. i don't know whats going on with it.

 

Im having a similiar problem with my firebird. But when i try to turn on the fan, i hear a few clicks and a hissing sound and thats the end of it. Fuse is fine. Maybe relays?

 

I believe this is called the vac selector switch. Its the switch that controls if you want the ac on vent etc. I saw smoke immediately i saw what it was. the vac switch was melted. and i believe this is what kept blowing the fuse. I however replaced the blower speed switch think this was the cause of the problem. doesn't hurt to replace them in our cars anyways. they get wore out and old. The only problem i'm having is finding this vac switch if thats what its called. If anyone could please let me know if this is something i can get at an autozone, napa. etc that would be great. I'll go there tonight and get it. Sux to have no heat. If anyone could please help me asap that would be great. Thanks

 

I've got a similar problem, but not Identical. I figured I would post on a similar topic instead of starting a new one.
I pulled my Heater controls and My plug is melted a bit but still working. How many amps should that unit pull? Also when I turn my switch to high it goes dead.
I'll try and get a picture to better illustrate what I'm talking about

 

high speed relay perhaps Hargrave? I know mine's out.

 

Seems like I remember a post from a long tiume ago about blowing weak heat. If you have swapped your factory radio out and put in an aftermarket there is something behind the radio that can become damaged and effect the blowing of the top vents. I can't really remember what it was but it happened to me when I took out my factory but since I don't really drive too much in the winter I didn't care. However if someone remember what I am talking about I would fix it just to have it right. I think it was some kind of line.

 

How does one check the voltage at the blower motor? Where should i put the probes to test it?

 

buell0303..... I believe that is a dealer item. The heat/AC selector is called the head unit. The part you need is the head unit switch. I recently replaced this on my RS. Good luck !!

 

i found it at autozone. It was under Fan switch in there system. It took us like 30 min to find it. but i got it installed. NOw i have another problem. The fuse is still blowing when i turn it on any ac mode or i guess whenever the compressor turns on. Does anyone else have this problem. What do I need to replace now?

 

Personally, I would start poking through my harness and see if something got hot or smoked. Sounds like you have a dead short.
And I would stop shopping at Autozone for electrical parts. I couldn't tell you the number of times I've installed parts from there that were defective out of the box.

 

from what i can see the harness looks good. theres got to be some kind of switch that tells the compressor when to turn on and off. Its got to be that which i need to replace. Does anyone know where that is located in our cars?

 

Unplug the compressor. See if the fuse still blows. I'm trying to remember my harness. And I don't remember anything special when I stripped mine out to go from TPI to Carb. As I recall there were like three wires that went to my compressor (Mine was missing) The only thing your head unit should do it tell the clutch to engage. And I think it's pretty much a directly wired thing. I do however remember a small group of relays and a small mystery box, on the firewall between the fender and the Brake booster. I don't think they had anything to do with the AC compressor but you can look. There is also a relay down near the Charcoal cannister. I'm not really sure what that does either. My guess is electric fan. The reason I don't know is the harness on my car looked like it had lost a fight with a weed-eater, totally non functional.

Hope this helps.

Mike

 

Thanks mike I didn't blow a fuse when i had it disconnected. but i think i found the problem. the plug that plugs into the back of the compresor theres two wires i found wire exposed and i think it was shorting out.

 

Problem Solved. I typed the wires up and my AC blows cold. Main thing in florida is the weather changes daily. one day you need ac the next heat. Just glade it works hard to see out foggy windows with no defrost.

 

glad I could help