87 Hvac problem
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Joined: Jun 2006
Posts: 80
Likes: 0
From: Northport New York
87 Hvac problem
I just bought an 87 coupe with an HVAC vacuum problem I couldn't figure out why I couldn't get heat once the car warmed up. I thought it was the blender door, but i took that peice out to view it and it is moving as it should, however i noticed that the heater core shut off valve was not moving. when changing the unit from hot to cold, i pulled off the vacuum line the valve opend right up and I had all the heat I could need, the valve only closes with vacuum, otherwise its open. for some reason the vacuum line has a constant pull regardless of what temp or function i put the climate control on.... any idea what this could be???? is there an HVAC vacumm diagram for this car I could try to find out why it has a constant vacuum pull. I have the line lines off and plugged for the winter but id like it to work properly thanks!
Team Owner
Joined: Jan 2003
Posts: 20,305
Likes: 240
From: Summerland B.C. Canada
Programmer or controller problem, leaning more to programmer.(assuming electronic climate control) 
http://members.shaw.ca/dankai/HVAC%20Electrical.pdf
http://members.shaw.ca/dankai/HVAV'S.pdf
http://www.batee.com/corvette/acrepa...oard/index.htm
http://forums.corvetteforum.com/1568603057-post3.html
http://members.shaw.ca/dankai/HVAC%20Electrical.pdf
http://members.shaw.ca/dankai/HVAV'S.pdf
http://www.batee.com/corvette/acrepa...oard/index.htm
http://forums.corvetteforum.com/1568603057-post3.html
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Could be the programmer. That's what takes the commands from the controller and switches the vacuum to the various HVAC actuators.
I'm going to be looking at this closely in the near future because on my car the air doesn't seem to come out where I think it ought to come out. If I put it in ECON, most of the air comes out of the heater outlets in the footwells. I think it ought to come out of the dash outlets. Results will be posted in my other thread on the HVAC programmer.
I'm going to be looking at this closely in the near future because on my car the air doesn't seem to come out where I think it ought to come out. If I put it in ECON, most of the air comes out of the heater outlets in the footwells. I think it ought to come out of the dash outlets. Results will be posted in my other thread on the HVAC programmer.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I just updated the HVAC programmer thread, so here's a link:
http://forums.corvetteforum.com/c4-t...schematic.html
http://forums.corvetteforum.com/c4-t...schematic.html
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