Two HVAC issues

[skwillard1983]

Overview:
It's a 2002 Explorer I bought it about a month ago. There were two issues, which I believe are separate problems: (1) It only blew hot air, even when turned to cold, and even though it was only ~40' outside. (2) It would blow to the windshield or dash vents fine, but not to the floor.

Observations:
I inspected the floor door thingy (actuator?) behind and left of the glove box and it seems to be working. I also noticed that the strange plastic item left in my glove box from the previous owner was a blend door motor (new and uninstalled or used and bad, I don't know). There is no ticking sound at all, which I know from the forums to be common with some of these issues.

Then about two weeks ago it started blowing only cold air, but still with nothing coming out the floor.
(1) I think the hot/cold air issue is either the blend door or the heater control valve. This would mean at some point the valve in question changed position to switch from hot-->cold.
(2) I suspect the floor vent problem is the Floor Door (not the control motor for the door).

What steps should I take to diagnose/fix these two issues (considering energy, time, cost, etc). Also, feel free to comment on my thoughts.

 

[zpn_by]

Check the screw and gear on the loose part to see if it has older discoloured grease all along the screw and gear. Two possibilities: new or used part but last owner gave up before repairing, or this is the old one.

Do you have manual or auto climate control? I had no heat in my truck with auto conrrols, and it turned out to be a valve on the heater line over the passenger exhaust manifold. Replaced for $45 and got heat back. Check this if you have auto conrrols-have to remove the intake snorkel first.