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One of these days I have to stop driving the car on my day off and fix the heater control while it's still nice out. I suspect the vacuum lines going to the control are cracked or fell off or something. What do I need to do to get to the heater control so I can repair the vacuum lines?
You're gonna have to supply a bit more info if you want some help. I see your profile lists a 79, so I presume that's what we're talking about. I did a fair bit of work on the climate control system on my '81 this summer and the two years are the same in that regard to the best of my knowledge.
Give me an idea of what exact problems you are experiencing and I'll see if I can be of any use.
With the engine running, place your head close to the Heater & A/C Control Assembly...
If you hear a hissing sound (a vacuum leak), it's possible that the valve body has come apart and regardless of where you move the controls, none of the vacuum controlled doors will move from the position they were in when it failed.
The valve body was held together by a small (50 cent) plastic clip. The one on my then new, '77 Corvette broke within the first year. The good news is that after removing the side panel it is very easy to access the Control Assembly and diagnose/repair it if necessary.
Here's a pretty useful illustration of how the Heater & A/C Control Assembly interfaces with the vacuum lines and electrical controls inside the console, courtesy of Paragon Reproductions... https://www.paragoncorvette.com/corv...alog/c3/#160/z
If the vacuum select switch is just leaking, take it apart (easy, just remove the center pin) and re-grease the switch with some high vacuum or dielectric grease... Here is a thread that'll show you.
Sorry... Yes, 1979. I can hear the hissing, I am wondering what I need to do to get access to the control, do I need to take the seat out to get to it? Do I have to take the console out?
Thanks for the link Wilcox. That may be very helpful.
The 1977-82 Console Side Panels (8921K-24K below) tuck into a groove in the Parking Brake Cover and the Console Top and are retained by three screws in their sides. Remove the screws and tug down on the panel and it will pop out. Image courtesy of Paragon Reproductions...
You should be able to access the Heater & A/C Control valve body through the passenger side panel. You may be able to reach the rearmost screw with a short phillips screw driver by pressing down on the seat cushion. The other two screws are easily accessible. It's been a few years since I removed one but I believe that is how I accessed mine. If you have the '79 and later Pace Car seats, you may have to remove the seat. At least remove the front two bolts and loosen the rear two. You should be able to tilt the seat back enough to access the screw.
You won't necessarily have to take the seat out to remove the carpeted console side panels. Like Gusto says above, there are three screws in each panel the ones at the front and back are easy to get. The one in the middle is a little bit tougher, but I just slide my seats forward and push down on the side bolster while undoing the screw with a medium sized screwdriver. If your upholstery is in great condition you may want to remove the seat instead. It should be easy, just 4 bolts. Be gentle removing the panels as they tend to break at the narrowest part.
To access the heater control you will have to remove the console. The vacuum selector switch, which is often the problem, is too tough to get at otherwise. The switch itself is a piece of cake to replace once the console is out. Be gentle with stuff wounded to the console though - lots of brittle plastic under there.
Curious, do you have any control over which vents the air comes out of at all, or is it always just the floor vents? Also, can you control whether you have really hot air or moderately hot air from the vents (it seems no corvette actually blows cool air)?
Last edited by StDomingos; Sep 20, 2015 at 08:32 PM.
Ok, perfect! Thanks for the help. I don't have any control over the vents, I can hear it hiss, and I do have "warmer than it should be" air coming out of the floor at all times.
Heater control quick question
