I'm getting very low airflow out of all of the cabin vents. I've already checked and cleaned/replaced the airfilter and cabin blower fan and the ducting between the two, there's no obvious debris at the intake. The blower and resistor are working fine - when removed but left connected to the electrical, it starts up fine, is quiet, and changes speed appropriately when the fan speed in changed.

I think there's either debris or something buggered in the system that controls the vents, but I'm not sure how to check that. Ideas?

 

I have to ask...
You did pull and inspect the cabin air filter, right?

Could be that mud wasps (assuming you live in an area that they are in) could have built nests in the ductwork prior to the filter... or spiders...ect..

 

Air filter was the first thing I checked, but yea, I've certainly forgotten to check the obvious before. Didn't come with one from the factory, so I figured it might have gotten clogged up with debris at the evaporator. Pulled the cabin fan, and stuck my phone up in the duct to look at the evaporator. Evaporator looks fine. Vacuum system seem to be operating properly, the door above the fan to select between outside and recirculating air is operating, and I can hear the vacuum system operating the other doors when the car is shut off.

 

I'd check the voltage at the blower motor when HI is chosen. It should have battery voltage. Unless you have an automatic temperature control system, the motor has multiple speeds selected and operated by an array of resistors. The automatic has a PWM driven power supplied to it. The Pulse Width Modulator could be failing, and not providing good voltage to the blower motor. You could also pull the blower motor and watch it operate at different speeds to note if it has the proper output.
It is either the blower (and power) or the ductwork. Or it is your imagination. Or it is the popsicle sticks, stuffed animals, old McDonalds wrappers, and the candy cane from last holiday season that is gumming things up. Things may have migrated down into the gizzards from the defrost vents, and are hindering 'flap' movement.
Good excuse to buy an 'inspection camera' from Harbor Freight to look into the plenum and such w/o taking it all apart... about $60-70...
tom

 

Didn't come with a filter?

2005-2012 Ford Escape Cabin Air Filter Check - 2006 Ford Escape Limited 3.0L V6