Yes. It is one of three things that could be causing that problem. The other two are the temperature blend door actuator and the heater core.

 

I had two problem, which was a vacuum leak & the heater control valve. First make sure that your vacuum lines are good. Vacuum lines are under the dash board.I have heard that sometimes people by mistakemight kick the line loose. So look under the dash board and inspectallthe lines.Also, inspect the lines that going from thefirewallfrom the motor copartment. After you have verify that the vacuum lines are in good working conditions. Then you must find out if your car has an heater control valve because my car is a 1989 MGM. Also find out if the actuator door open/closed by playing with the dash board buttons.The heater control valve only solved the heat which for the floor on my car. So concentrate on the vacuum line first,then on the actuator doors. Let me knowhow it comes out.Edited by: pdman

 

Ok, onewheelpeel I will try to answer your question. Question,the heater control valve, would that also solve a problem where the AC works but the heat does not. Yes, the heater control valvecontrol the heat in my car due tosometimes i did not get heat at all and their were other times that i got some heat. After, i replaced it the heat/ac works all the times. My problem was solved but first you must find out if you have one in your car.Also, if you are going to buy it buy the motorcraft one not the aftermarket one because i had thesame problem with the aftermarket one.So i hope this answer your question.[img]smileys/smiley14.gif[/img]

 

Is there a Factory Service Manual that I can download from somewhere for my year?

 

I get most of my info from the Chilton book. Whatever, info you want to know about your car is in that book. Most of the time you can pick it up at your local library, or purchase one from your auto parts store.