1998 Expedition XLT heat problem

[tlbrwb]

I recently purchased a 1998 Ford Expedition XLT and have discovered that I only have heat in the rear two seat areas. The dash panel, defrost, and floor all blow ice cold air even when the rear areas are blowing heated air.

Can anyone give me an idea what is going on and where I should look next. I replaced the thermostat, but that did not fix the issue. Any help is very appreciated. Thank you.

 

[fiveohpoepoe]

Blend door in the dash is a good place to start

 

[walnuts4x4]

+ 1 for blend door or actuator of the blend door.... look up heatertreater.net i believe.... is a way to fix it without removing entire dash