ok... on my 87 TC everything works but,.... the heat. its got all the basic stuff like thermostat, heater core isnt bypased. i havent had a chance to play with it, but i figured id ask around and see if anybody has any experiance with em. all i rember is they are very complicated, and a pain in the ass
It's likely the temp door in the heater box - either the door is jammed (I've seen them jammed by pens, lipstick tubes, drinking straws, leaves, mouse nests, and "W's Drawers" - in some cars the door is covered by a black silky looking cloth that comes unglued and jams the door, and when you pull it out it looks like a wadded up pair of panties) or the actuator is not working
could also be a broken vacume line.
hmmm, how hard is that door to get to, can i pop open and let down the glove box and get to it? or do i have to remove the dash, or at least pull it out while still connected.
The EATC system does not use vacuum to control temperature, it uses a bi-directional stepper motor actuator.
For that matter, neither does the manual system - it uses a cable. A vacuum leak will only affect where the air comes out on a manual system, not its temperature (a broken vacuum line will usually result in defrost only, as the vacuum motor actuators will default to defrost for safety reasons)
Nate: I've never had an EATC system problem, so I can't say how easy it is to get at anything, but judging by the diagram (see attached PDF) I'd say the blend door actuator should be facing the back of the glove box door or radio/HVAC stack, so you should be able to get at it. Try removing the actuator and see if you can move the door by handf