Any and all suggestions are welcomed guys. Here's what I have so far.

Heat does not blow hot air.
Both lines out of the heater core are screaming hot.
Replaced vacuum line from under battery tray to by the throttle body.
Does NOT switch from floor heat to defrost heat upon acceleration.
A/C blows ice cold air.
When defrost is selected and hot or cold position for thermostat is selected, blows ice cold air up onto the windshield.
Switches from floor, to defrost, to any combo of those two with the turn of the selector, just like it's supposed to.

Please help, it's cold enough in the mornings now to need hot defrost to clear the windshield.

Thanks,
Jay

Temp door sounds like it is not working.

Temp door sounds like it is not working.

How do I check it and where is it at?

Thanks,
Jay

Under the dash in the heater plenum. Sometimes called the blend air door. Should be a vacuum motor that moves the door. Look for the hose off. Right in front of the passenger.

Thanks, I'll start digging there.

Jay

Same problem on a 99, is the temperature door vacuum or electrically activated on my model?