Mercury mountaineer heated seat wont turn off

SOURCE: 2004 mercury mountaineer.heat problem When turning

Most likely the blend door actuator has a stripped gear on it causing the noise you hear. Since it runs repeatedly the stop on the gear has sheared off making it run like this

SOURCE: Heat does not work, makes loud clicking noise when

I have a 2003 Mountaineer that had the same symptoms. After doing some research, me and Google decided it was the Blend Door Actuator. It is a fairly difficult job due to having to take pretty much the whole dash off, but I did it myself with minimal experience. I included a few links.

http://redhouseon7th.com/redhouse/howto/2003FordExplorerBlendDoor/ (This is the guide I used.)

http://www.explorerforum.com/forums/showthread.php?t=212667

Good luck!

SOURCE: 2004 mercury mountaineer.heat problem When turning

2004 mercury mountaineer.heat problem
When turning ac knob to heat clicking sound like door opening and closing repeatedly sounds and air blows cold instead of hot.

SOURCE: 2004 mercury mountaineer driver side

It is very common for seat heaters to fail. You can disconnect the heater from the wiring and place a voltmeter on the wiring. If you get a reading, then seat heater is bad.