Whether I have the air or heat on, it seems like there is a minimal amount of air coming through the vents. The fan works on all speeds...low to high. Any ideas as to why there'* no airflow?

i would check to see if you are getting full voltage on high at the blower motor connector. that will narrow down what your problem is. if you are, could be a diverter problem, some buildup in the evap or heater core, motor could be going

If it has blend door accuators you may have one or more froze up. You can usually pull them and take the top off and free up the motor. I've had to do it a couple times.

How do you pull these out? They seem like they twist on or something?