Where is the module that controls the heat/ac vents.

SOURCE: front panel temperature control switch

Very likely the blend door is broken. This door is mounted beside the heater core, blends cool air with hot depending on the position of the door. At the bottom of the door at the hinge point, there is a gear and coupling driven by an electric motor to position the door. The coupling is a drive much like a square drive ratchet and socket made of plastic and often cracks allowing the drive to turn without changing the door position. I've heard you can drill through the outer housing and put a screw in the door through the drive gear, but you would have to know your way around this area well.
I repaired mine by replacing the blend door, a big job at best. The entire dashboard must come out to access the top of the heater core housing which must be removed.

SOURCE: ac only blows through defrost vents

I just found my problem that often brings in a Check Engine light, and reads out a PO 442 code. When my A/C is on my heater would start working because a vacuum operated control door would slam shut when accelerating. Also my cruise control would stop when going up a large incline.

the first thing to check, and easy is the cruise control for a bladder leak. Look on the top side passenger side of the firewall, and you will find a three way vacuum hose connection. One will be a very small black plastic line that runs to the cruise vacuum actuator. Pull this hose loose at the fire wall connection. Blow in this hose, and if it will not hold pressure, and in my case I could hear air passing through it is defective needing replacement. Block off the firewall connection for A temporary fix.

SOURCE: AC does not work. Heater on always even when turned off. Told I needed a climate control module.

If it is a digital control modual they were known to go bad.

SOURCE: only hot air comes out of vent with ac on

Blend door motor has malfunctioned, or has a vachum leak This needs a lot of tools to test and fix, it could be the control head bad as well. so Let me know if you have the tools and the time ability to do this and we can do a diagnostic fix on it.

SOURCE: Recirculation fan motor (ac/heating) and mode

yes there is a fuse.. does it work on any fan speed or none at all?