So out of nowhere air no longer comes through my vents and I can't figure out why.No fuses are blown, blower motor is running, I see two blend actuators and they move when settings are changed, there is no cabin filter in 98's to clog, no vacuum line issues that I can find, you can hear the vents change settings when you adjust the ****, just no air blowing through them.
What am I missing. Any help is greatly appreciated.

 

Blower motors have a wheel on them that create the air flow, this wheel normally has a hub on it and sometimes (If Bad) it will just spin in the hub but the wheel wont turn.... do you hear any noises?

 

if i am not mistaken, theres a blend door, and a servo door for the floor vents, defroster and dash vents. if you switch from cold to hot, does anything change. if air blows when selected in hot, its your blend door. possibly sticking or bad servo motor...

 

As far as noise it is loud as hell but, it seems to be spinning. Both of the blend doors that I can see, 1 by the blower motor and 1 on the center floor are working. Is the another blend door that I'm missing? In the dash maybe?

 

according to alldata there is a temperature door in the middle of the hvac casing. or your mode servo, the one close to the driver area, may not be connected to teh actual flap that controls the air flow. go back and check and maybe remove the motor and try and move the door flap manually.

 

My 97' does something very similar. It does what its supposed to do for the first 20 min. of driving. Unless you leave it on high the whole time it never slacks up. But when you put it on low for a while it quits blowing outta the vents. So I crank it back on high then it gradually goes back to blowing hard. Its like a door closes when the fan slows down too long?
Any help would be appreciated.

 

I as well have the HVAC demon to contend with in my 97 in my sig! everything in mine works except the damn selector it is everywhere all the time! but hey!, the temp **** works atleast lol.