2003 Explorer noise from left rear fender well

I have a 03 explorer with rear a/c and heater that has a clunking noise when the key is in the on position.The noise seems to be coming from the rear heater core or the rear a/c evaperator.I thought it was the rear blower motor,but noise is still there even when blower motor is disconnected.
Has anyone experienced this problem or have any ideas?
Any thoughts or ideas would be appreciated

There is a blend door actuator and an air distribution actuator.

Open the rear door pull off the weather striptowards the rear. There are two rotating clips to remove the panel with the seat belt retractor. Remove the rear panel.

You can feel the actuator clicking. replace the bad one with an (if I remember correctly) 8MM socket.

The part is about $95 from the dealer and about $50 online