78 Climate/ heater control question
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Joined: Feb 2019
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From: Pgh Pa
78 Climate/ heater control question
I tried to research this before I ask this question. I tried using a Mity Vac to get vacumn to the control from the T under the hood, as this is the source of vacumn. I could not get any thing on the gauge. I am trying to get air flow to the upper vents and defrost, as now everything comes out the floor. So I am assuming that I have a leak between the line under the hood to the #1 nipple on the control. Should I finish dismantling the dash and ducts to check the lines?
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Joined: Jan 2014
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From: Hermitage TN
If the problem is like what I had/have it's probably the vacuum control switch. Check out this post
https://www.corvetteforum.com/forums...on-switch.html and the information posted by Finix2835. I did not have the High Vacuum Grease so the cure only lasted for about two weeks as I used another type of silicone grease. I will be ordering the High Vacuum Grease and will try this fix again.
https://www.corvetteforum.com/forums...on-switch.html and the information posted by Finix2835. I did not have the High Vacuum Grease so the cure only lasted for about two weeks as I used another type of silicone grease. I will be ordering the High Vacuum Grease and will try this fix again.
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Joined: Jan 2014
Posts: 74
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From: Hermitage TN
I purchased new control switches in the past and still had the same problem.. In my opinion the new switches aren't worth the money. I also purchased these items to put the switch back together. I did have to file the screw head down to make it fit.
8-32 x 1/2 nylon screw
1/4 nylon washer
8-32 nylon nut
8-32 x 1/2 nylon screw
1/4 nylon washer
8-32 nylon nut
Le Mans Master
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From: Indiana
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Le Mans Master
Joined: Jun 2019
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From: Indiana
used small amount dielectric grease works fine..are you sure its tight enough? Heard replacements iffy...try using original repair as mentioned
Melting Slicks
Joined: May 2015
Posts: 2,365
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From: Cape Girardeau Missouri
I bought a new "modified to not leak" switch from one of the vendors and guess what? It leaked! I opened the original and used a little bit of high temperature "plumbers" grease and it has worked for over two years.
From what I've learned never, ever install a vacuum component (be it new, used or reconditioned) without testing first! They should hold vacuum overnight with no leakage as indicated by a Mitee Vac gauge.
From what I've learned never, ever install a vacuum component (be it new, used or reconditioned) without testing first! They should hold vacuum overnight with no leakage as indicated by a Mitee Vac gauge.
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Joined: Feb 2019
Posts: 77
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From: Pgh Pa
It already has a replacemnt control when I got it, the orginal is long gone. I ordered a tube of high vacuum grease today and will try it when it arrives. There was never any airflow from the upper vents when the PO had it. I figure they change the control still leaked so they disconected the vacuum line at the T under the hood.