well I'm having the same problem with my 2004 Ford Explorer and Ford told me it will cost any where between 700.00 and 1800.00 dollars...
Remove the dash assembly to gain access to the blend door actuator.
The blend door actuator can go bad. Big job to replace it. Dash assembly must be removed to gain access to it.
Unfortunally you need to remove the entire dash assembly in order to gain access the the blend actuator. Consider replacing the heater core while your in there only because the amount of work involved to do it later if it should leak.
How do i replace blend door motor
how to replace a blend door actuator on a 1999 ford ranger
You have to take the front dash apart almost to the firewall. A lot of 5,8and 10mm screws. Not a job for a DIY'er.
how do you replace a blend air door assembly on a 2000 pontiac bonneville
The blend door actuator on the late model Chevy Tahoe is located behind the dash in the glove box area. Broken blend doors and broken blend door actuators are a very common problem among Chevy Tahoe, Suburban, and Silverado models. Typically, to repair a broken blend door, a mechanic will disassemble the dash and replace the plenum box. It is an expensive and labor intensive repair. There are also some DIY solutions such as the heatertreater that provide hardware and instructions for performing the repair by removing the glove box rather than the entire dash. It is worth looking into if you think you have a broken blend door.
the blend door actuater is more than likely the cause of the noise.....very common....can go in behind the glove box to replace it.
If you do a Google search on Ford Explorer blend door there are lots of articles
depends on which door your talking about but its located under the dash pad on the passenger side up against firewall and requires you to remove the entire dash and tilt it forward and down
To replace a blend door on a 1999 Voyager, you will begin by checking which side of the vehicle is not receiving heat. Then, remove the glove box door by squeezing the inside of the door toward the center of the door to access the blend door.