I bought a 1988 Firebird that has been sitting for 19 years. I knew the moment I turned on the HVAC fan there was a mouse nest as it made a groaning sound and when it did spin it vibrated like crazy. I took out the fan and huge nest. Spent a couple hours cleaning the squirrel cage and the duct area. When the fan is on high it doesn't seem to blow very hard. When I had the instrument cluster out I vacuumed out the center and drivers side vents. There was nothing in them. I am thinking that there is more nest on the intake side of the system. Where are the ducts the suck in air into the system or where should I look next.

 

Does the fan motor change speeds with the switch? It could also be a weak motor or resistor on the way out.

I believe the intakes are at the cowl, below the wiper blades.

 

The fan changes speed and it seems to be running well. Just doesn't seem like that much air pressure. I had the wiper cowling off. Car needed a windshield and I did vacuum out that area. AC still not working (Neither the compressor clutch nor the cooling fans are coming on.)but the selector switch is changing where the air comes out of. Saw a video about fixing the switch at the back of the heater controls, mine is solid. I have another one someone gave me and it definitely needs the round switch repaired with the nut and bolt as in the video.

 

Yes, the intake air comes from the cowl area below the windshield. Seeing that the area on the cowl side of the firewall and the inside of the squirrel cage were filled with 'stuff' indicates to me that they were mostly on the outside and you may have gotten kind of lucky on that point, unless you had already cleaned the evaporator box area before the picture was taken. Hopefully that insulation came from a neighboring car, and not this one. That's a LOT of insulation, and probably from the interior along the firewall.

Note that if you replace the squirrel cage, I found that the aftermarket has done their (poor) job again, and it won't fit well. I had to significantly modify the evaporator box are around where the blower motor fits before I could get the blower to run w/o buzzing loudly as it self-clearanced the housing. I had to replace the blower motor on our B4c, and found that the OEM squirrel cage didn't fit the stud on the new motor. The aftermarket cage was 1/8"-1/4" out dimensionally vs. the OEM cage.

 

To the right of the fan I could see the evaporator. There wasn’t any nest material down in there. I wish I had stuck the leaf blower down there to see if there was anything on the other side of the evaporator.

 

Remove the top half of the cover on the evaporator and should be able to see both sides of it. Maybe the heater core too as air has to pass thru there too.

 

Check out my thread: https://www.thirdgen.org/forums/memb...ld-thread.html
Post #43.

Remove the top of the AC box and pull the evaporator. Also, pull the cover for the heater core. All of this stuff is interconnected. So you need to open it all up to get it cleaned correctly.