AC/Heater control Vacuum hoses
Thread Starter
Intermediate
Joined: Feb 2002
Posts: 26
Likes: 0
From: Simi Valley CA
AC/Heater control Vacuum hoses
Alright, I have a 75 coupe I purchased in AZ, After bringing her home a few months ago I found out that CA has very strict Emmission Laws. The Forum had a lot of answers for me. Most of the problems I've had in the past months came easily solved through Reading publications, Internet searches, other owners I know, and the Forum. The newest problem is the vacuum tube system for the AC Heater control. Does any one have a diagram of it. I need to figure out which tube is suppose to operate the heater hose shut off valve. I dont have a tube that isn't doing anything and the GM assembly book wasn't any help. in advance THANKS Jim (new at restorations and having a blast)
:confused: :D :cool:
:confused: :D :cool:
Le Mans Master
Joined: Mar 2002
Posts: 7,056
Likes: 40
From: Life is Messy, Bring a mop
Re: AC/Heater control Vacuum hoses (Viking88)
Are you sure it isn't the astro vent vacum line? This comes from the heater control and opens and closes the vent (on the rear bulkhead).
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Re: AC/Heater control Vacuum hoses (Viking88)
If you have factory AC then there is no heater hose cutoff valve...weird huh? I set up my own valve and spliced into one of the vacuum lines coming out of the control unit...can't remember which one but, the control is diagramed in the Assembly and Installation Manual (AIM) which you can buy at swap meets and corvette only part stores. What I found of best use is the table showing which hoses received vacuum, and which ones were open to air for each setting. I located the hose that supplied vacuum when the shutoff valve wanted it and bought a vacuum T and some more vacuum line and ran a line out through the firewall where the other lines thread through. Interestingly enough there IS an empty hole to add another line...so even if you don't add the extra line for an extra cutoff then you should plug it, unless you enjoy the engine compartment odor that wafts in every now and then.
