Heater A/C Vacuum woes
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Joined: Dec 2002
Posts: 83
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From: Everett WA
Heater A/C Vacuum woes
I've got an 87 with electronic climate controls. The heat and A/C doesn't blow out of the proper vents. I can't quite seem to figure out if I have a vacuum problem or an A/C programmer problem. When I pull the vacuum line off the spherical vacuum tank, it hisses (got vacuum there). I relaced the check valve up near the distributor. That should be fine. Before I go and replace the expensive A/C Programmer, I'd like to check the source for vacuum that must go to the programmer. I have a GM service manual, but I can not tell where the vacuum line penetrates the firewall and connects to the cluster of vacuum lines connected to the programmer. The service manual makes it look like there is some sort of check valve somewhere near the center of the car that splits into at least two vacuum lines. Any idea? This is really frustrating!!!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Re: Heater A/C Vacuum woes (87Vert)
Just to the left of the distributor - towards the battery is the check valve. Vacuum source is from the right side of the plenum, next to the source for the fuel pressure regulator. Line for the programmer is behind the engine after the check valve. Usually if you can locate the check valve, you can follow it to the firewall - it's really tight though.
Pro
Joined: Aug 2000
Posts: 666
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From: Richmond TX
Re: Heater A/C Vacuum woes (87Vert)
The supply line enters thru the wire loom thru the firewall! behind your control head, it splits the feed the doors. I had the same problem, but couldn't get to the supply line without taking the dash apart. My solution was to run a new supply line to where it splits behind the control head. Maybe not the optimal solution, but it worked, and I didn't have to take the dash completely apart!! :party:
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Joined: Dec 2002
Posts: 83
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From: Everett WA
Re: Heater A/C Vacuum woes (mk842766)
Thanks for the help! Hopefully I'll get a chance to run this one down this weekend. Following the line after it leaves the checkvalve has been nearly impossible. Last night I did disconnect it at the checkvalve and it hissed at me, so I may have vacuum there, but I really want to check it where it splits off to the A/C programmer.
