79 HVAC control
Thread Starter
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
79 HVAC control
I did some work on the dash and console in my '79, during which I replaced the heater/air conditioning control in the console. I now find it has no effect on the air distribution. No matter which position I put the upper lever in, the air comes out the lower (heater) ducts. I did a search on this forum and found a couple of threads where others had similar problems, and it sounds a little like some of the aftermarket controls are not assembled correctly and do not work as they should. Unfortunately, I couldn't find a thread where anyone had solved thier problem and posted the solution. Has anyone had this problem, and solved it? How?
Burning Brakes
Joined: Apr 2009
Posts: 807
Likes: 2
From: VIRGINIA BEACH VIRGINIA
Over on the passengers side along the tranny tunnel there is a cable (black) and about halfway down there is a plastic adjustment that connects two parts of the cable together. Mine was not tightened all the way down. If you pull the tranny tunnel carpet on the passenger side you will see what I am talking about. Also, it could be a leak. start pinching hoses in the dash until the control works.
The hoses that go up in to the dash behind the glove box are a beotch to route and the hose going out to the heater control valve (below the ac unit) in the engine compartment was leaking on mine also.
The hoses that go up in to the dash behind the glove box are a beotch to route and the hose going out to the heater control valve (below the ac unit) in the engine compartment was leaking on mine also.
Thread Starter
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
Update on my HVAC control problem. Last year I replaced the control in the dash just before I put the car away for the winter, so I never noticed that the air was not being distributed properly to the vents or ducts. Today I did some troubleshooting and to make a long story short, the vacuum control on the new unit doesn't work. I swapped in the old vacuum control and everything works fine. It appears to be another case of an aftermarket part that doesn't work the way its supposed to.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
In most cases when the vacuum select switch is not working, a drop of oil in one of the tubes will solve the problem. If you take the select switch apart you'll notice it looks like two plastic maze's compressed together by a plastic rivet with a tension spring keeping them tight.
The only thing that keeps them working properly is the lubrication between the two sections and placing some 80 weight oil in there will in most cases will solve it. Getting a few drops in one of those small tubes can be a challenge though.
Willcox
The only thing that keeps them working properly is the lubrication between the two sections and placing some 80 weight oil in there will in most cases will solve it. Getting a few drops in one of those small tubes can be a challenge though.
Willcox
Thread Starter
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
[QUOTE=Willcox Corvette;1580307628]In most cases when the vacuum select switch is not working, a drop of oil in one of the tubes will solve the problem. If you take the select switch apart you'll notice it looks like two plastic maze's compressed together by a plastic rivet with a tension spring keeping them tight.
The only thing that keeps them working properly is the lubrication between the two sections and placing some 80 weight oil in there will in most cases will solve it. Getting a few drops in one of those small tubes can be a challenge though.
Seems reasonable although I'm not going to try it since I already have it working with the old switch. It would be easy enough to oil the new switch since it is held together with a clip that makes disassembly easy. I wonder though if another lubricant might be a better choice. Oil doesn't mix well with some rubber products, causing them to swell and break down. Perhaps a silicone lube?
The only thing that keeps them working properly is the lubrication between the two sections and placing some 80 weight oil in there will in most cases will solve it. Getting a few drops in one of those small tubes can be a challenge though.
Seems reasonable although I'm not going to try it since I already have it working with the old switch. It would be easy enough to oil the new switch since it is held together with a clip that makes disassembly easy. I wonder though if another lubricant might be a better choice. Oil doesn't mix well with some rubber products, causing them to swell and break down. Perhaps a silicone lube?
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
I don't blame you, it's working and you know the old saying.. Ain't broke....
Usually when you take them apart they break. The oil trick is one that has been used since the late 70's and one that I learned from our "New Car Get Ready" mechanic at the dealership.
It has always stuck with me since.. about thirty years.. LOL
But the heavy oil won't hurt the ABS plastic the switch is made from..
IMHO,
Willcox
Usually when you take them apart they break. The oil trick is one that has been used since the late 70's and one that I learned from our "New Car Get Ready" mechanic at the dealership.
It has always stuck with me since.. about thirty years.. LOL
But the heavy oil won't hurt the ABS plastic the switch is made from..
IMHO,
Willcox
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