86 944NA automatic and I have not had anyheat since I bought it. It's getting coldeven in North Carolina. No defroster action either.The fan works, fuses are good. The valve at the back of the engine is hooked up to a vacuum actuator. None of the doors in the heater seem to move when I change the settings on the control unit. Temp guage reads normal when I drive it around. I don't want to replace the control unit if I don't have to (~$600) - does anybody know what I should/could check? I have not been able to decipher the wiring diagram enough to know what pins to check for voltages to see if there is something else to check.
The A/C does not workeitherand probably has no freon in it - I thought I could address that later.
Appreciate any hints on where to start or what to measure/replace.

 

The vacuum valve defaults to the open position when there is no vacuum, so unless it is stuck closed, that shouldn't be an issue. See you if you can operate the arm manually on the valve and make sure it is moving back and forth. There is a little arm on the drivers side of the HVAC unit which has a clip which likes to break. If that $2 clip is broken, the heater temp controls will not work either.

Clarks-garage discusses this in detail with pictures of the rod and clip. It is a sub 5 minute fix, and about $2-3 in parts.

Go to www.clarks-garage.com and click on his shop manual. Click on H, and choose heater malfunctions. The last 2 pictures show what you need to see.

 

In my car I replaced the clip (as all I had was FULL HEAT!!!!) Now the lower control arm is moving but the upper control arm is not. I do not think that the defrost is working. Is this a vacuum problem or possibly a bad servo problem?

 

So I realized that the defrost on the vent wasn't closing the vent... So defrost is working... The issue seems to be that I still have HEAT blowing out onto the floor. I have the thermostat set between 18 and 21. Even with the two sliders in the less position I still get a good burst of heat blowing onto the floor... Do all 944's have heat like this or does mine just have an intense heater?