1990 sable heater

[wizardb]

my heater fan works well and the hoses going into firewall from engine are both hot, the vacuum solenoids switch from def to vent to floor with no probs but cant seem to get any heat. is there another solenoid for a blend door? if so where is it located? also it is one of those electronic controllers instead of the nice old style slides and cables.

[Slade901]

Not sure with your vehicle and I hope someone will jump in. However, with most older vehicles I've seen and experienced. If you are not getting heat inside the vehicle and you thing that the switch for different vent position works but actually they are not moving. Most of those vent switch are controlled by a vacuum and usually tied to the cruise control. If your cruise control is not working and probably tied to the air vent switches on the vehicle then possible there is a loose vacuum hose along the cruise control line.

[wizardb]

well the cruise works fine and with the glovebox dropped out i can see the vacuum switches and they are actually moving like normal. but i can only find three and my chiltons and haynes manuals are vague in this area only talking about how to replace heater core and blower motor . will try flushing and blowing out core tonight and pulling console apart to see if there is another switch for a blend door under upper end of dash. thanks for your response.

[Cntrysthbst]

Same prop. alittle while back, the door that opens and closes for the ac/heat was broken at the swivel point. I had to replace the whole air duct unit, and yes it holds the heater core and evaporater as well. The JB weld didn't hold and neither did melting the plastic back together. It was the biggest pain, I had to take out the WHOLE entire dash just to check and them had to replace the air duct assem. Hopefully you find something else wrong and this isn't your problem.

There is a vacuum diaphram that controls that door, on elec. climate control, you may have to take your dash apart somewhat to access it. Do make sure that when you see the diaprams working/moving that it is accually changing the air movement, etc., because the arm may not be attached at the door. I will check into this more cause I thought there where only 3 diapharms that worked everything. You can also check the diaphrams manually with a vacuum pump. Will get back with you.

[wizardb]

well that seems to be the problem the core is good and so is the thermostat . so where is this located at? i have found one behind the glovebox which doesnt seem to do anything except open a door for recycle air or outside air and i removed vacuum hose off it and used hand pump to activate it and the door opened. then from there i can see one towards driver side and it controlled the shifting from defrost to vent to floor and it does all those things with no problem. then there is a third one above that...real hard place to get to i can see it actuating but what it controls i am not sure......hope it is not the door you are talking about being broken off.......who is the stupid engineer that decided small plastic parts were better than steel ? thanks for your response thats more help than Chiltons or Haynes.

[wizardb]

well finally started on this project and took me two days to finally get dash off to see the heater core, still trying to find all the bolts holding it in place should have it out tonight. the blend door is controled by a electric motor on this one will know more tonight after getting it off. maybe the hinges are good and just need to replace the motor.