I have a 94 S10 Blazer and when I turn on the ac/heater fan, I can hear the fan going but nothing is coming out of any of the vents on any of the settings. i thumbed thru many posts on this topic but couldn't really find one where the fan did operate but no air is coming from the vents. I can definitely hear it on high and I think its working on the other settings too, I'm not sure though, I can barely hear it.

This is my first post, I just bought this thing the other day. Thanks.

 

Check the airflow at the defroster and the floor. If is then your vacuum system is not working.

 

If it is blowing in the bottom check the vacuum line coming out of the firewall to the left of the brake booster, that is the feed line for the controls and they are prone to break causing loss of control.

 

It doesn't seem to be blowing out anywhere. I have a theory though. I found an old mouse nest above the map lights, behind the overhead compartment. I might have a nest in the duct. The fan definitely rruns on all speeds and when I change the settings I can hear it change, but still no air from anywhere. I haven't checked the vacuum line yet.

 

dam mice got nothing else better to do

 

did it ever work? ive ran into this problem two times. one was i bought a suburban that sat in a field for a few years and yep a mouse built a house in the heatercore area. but it only blocked half of it. i really didnt think much of it i just figured it was a old truck, but after the heatercore had to be replaced i seen all the crap in there.

also had a 85 s10, previous owner actually put in a reverse rotation blower motor in there i couldnt figure it out for a while either. the heat did blow but high was like low and that thing being a rotted turd with all the holes in the floor it didnt get very warm in winter.

 

Could the fans' set screw have come loose? The fan motor turns but the squirrel cage fan just sits there. OR it has been blocked & now the fan is stripped where the fan shaft goes into it.

 

wonder if the Squirrel cage exploded. seen it before. that would be the best bet. pull the motor out, make sure its all intact and spinning the right way and nothing died in your heatercore area too