Minimal Air Flow - Even at High Speed

#1 The heater core and A/C evap care can get clogged with debris getting in through the fresh-air intake beneath the cowel. Removal of the blower fan assembly is necessary to get in there to have a look though.

#2 There is also a blower resistor on the fan housing that acts like a current sink for slower fan speeds, but if your fan slows and speeds up like normal as you slide the knob, it's likely not that.

If the fan rpm sounds the same as it did before, i'd look more for #1 than #2.

The controller can always fail, which isn't uncommon at it's age.

It's also possible that one or more of the vacuun actuators that are on the back of the A/C assembly have ruptured, which would cause mixing doors not to open to their corresponding vents.

A vacuum leak anywhere in the system can also cause the vacuum actuators to not properly function, usually this failure defaults to the defrost getting all the airflow.


It's pretty invasive to get in there and have a look. To pull the fan assembly it really helps to remove the glove box and passenger seat for comfortable access.

To get to the actuators, the whole dash needs removed.

Had this problem on a Corolla once. Turned out that the hood insulation was degrading and getting sucked into the fresh air intake blocking the evap coils.

+1 on z-karma’s comment. If you get in there and it’s clogged up with dirt/hair, use an a/c foaming coil cleaner to get the gunk off. Frost king makes a good one with a brush on the cap.