Here is my problem. When I crank my 02 expedition, sometimes the front ac works and most of the time it don't. The rear ac works fine. I can feel cool air coming from the front vents when I am driving down the road, so I know it is not the compressor. I changed the resistor a few weeks ago with no success. Any suggestions would be greatly appreciated.

 

This happened on my truck and one of my dads trucks. There is a servo motor behind the glovebox that goes bad. No tools are needed, just pops out and unplugs. It is controlled by the red/blue temp dial. Basically its job is to completely close the heater core if you turn on AC, and vise versa.

https://www.amazon.com/Motorcraft-YH...ords=ford+hvac

Thats for a 2003. SOmtimes AMAzon has their years off, so I would check another source.