I am not getting any heat. The AC unit blows cold air, When I put selecter into heat positions I can here dampers move. Temperature on engine runs normal ( both heat up time and running temp.) Reastate for temp control ohmed out OK. Heater hoses going into firewall both hot. All fuses inside of dash and under hood are OK. I do not know where Three wire plug that goes to selecter switch goes or what it does ( valve ? circuit board? damper door? any help would be appreacieated - Thanks Klee

 

Check down on the passenger side under the glove box to see if the ducting is warm/hot. There is a main door that opens and closes right there depending if heat or A/C is selected. One way blocks the evaporator core for heat and the other blocks the heater core for A/C. Check to make sure the arm for that door (and any other vacuum motor linkage) is actually moving it could be just the vacuum actuator your hearing move but not pulling the arm to the door. Holla' back and let us know.

 

The deeper I get the more I understand. I checked the actuaters by looking threw the Glove box hole as you suggested. Two are visible - One opens so that you can see the fan run when you are in MAX Air - The other does move in responce to the vent selecter switch.

 

Second part- did not mean to sed that - I now know I can not indent- What I have found out now is that I have air conditioning running no matter where the temp dial is, when vent slecter is in defrost. I veryified this by taking plug off AC clutch then I was getting heat on windshield. I rechecked Temp control ( reostate ) whith Ohm meter and you can see steps in reading. Any Ideas of what tells the AC unit not to run when temperature dial is fully to heat position? Wires went ino a harness and I was not able to follow. Thanks - Ken

 

The A/C is supposed to run in the "defrost" position. It will run even when you select "heat" on the control, it will just shut the door to the a/c and open it for the "heat" but the A/C clutch will still be engaged. Try to put it on "floor" and "heat" and see if the A/C is still running.