It's Hot in Here

[turismo177]

Hello all. I really enjoy reading all of the posts and have learned quite a bit. My '81 needed quite a bit of work when I bought it and I'm in the process of putting in new seats, new carpet, rebuilding the front end, etc. etc. Here's my problem.

The AC has been converted to R134. When I turn it on air will come out the defroster and at your feet but not out of the dash vents. Living in Missouri cooling the windshield doesn't do much for the poor schlub driving the car. ;help Does anyone have any ideas on where I should start to track down the issue? I have an new heater control switch but haven't installed it yet. Is there maybe a vaccum line off somewhere which is not allowing the air to come out of the vents? Will I need to pull the dash out to track this down?

Any help will be appreciated guys. I'm trying to get all of the work done so I can take it in for paint in the spring. Note: My Vette came with the t-top carrier option and I had one heck of a time finding them but finally had the opportunity to pay through the nose on ebay for a pair, luckily I had the straps already.

Thanks and keep Vetting.

 

[Nobody Cares]

There is a vacuum control at the back of the A/C Heater control. I believe it has 4 or 5 vacuum hoses connected there. I had one off on my 80. Could be you might just have a leaking hose . Had the same problem . Replaced it and walla everything worked as it should. I went in at the passenger side and took the counsel side panel ( couple of scews ) off. Then you will see where the vacumm hoses go to the control. Each vacuum hose is color coded ( white stripe , red stripe , ect. ) to indicate where it goes. If i can help any more just write and it will try to help. Dave

 

[Nobody Cares]

Number 3 is the vacuum hoses at back of controls

 

[Nobody Cares]

Hope this helps . Dave

 

[turismo177]

Thank You

Thank you so much Dave. You are awesome. These diagrams will really help. I really do appreciate your response and the time you put in. I love this forum.

Thanks
Terry

 

[Nobody Cares]

Thnx for the nice comment. If you need any more help , I'll try to help. Dave











:bar

 

[Nobody Cares]

Here's a little more detailed pix . Shows where each color striped hose goes and what the purpose is. DAVE

 

[tgg901]

No Defrost

My defrost doesn't work and I replaced the switch on my AC controls but still no luck. Any ideas???

 

[6880 Mike]

#3 actuator in the AIM pages above switches between defrost and dash vent. Check it.

 

[Nobody Cares]

Check the vacuum hose on the #3 or any of the hose's.It should be the black hose with BLUE stripe. I had the same problem , and it was a leaking vacuum hose that controls the door for the defroster. Just a thought. Dave

 

[tgg901]

Do I by chance need to take off the Instrument cluster /radio panel off to get to this #3 actuator?
I also took out the glove box and saw the water shut off valve switch and have a question. Does the button on the switch need to be depressed in the cold position? On mine in the cold position it is at the tip of the button but no contact is made. It make sense to me to adjust something until the button is depressed. Do you know if there is slots in the switch to make the adjustment?
I take it from the name that the purpose of this valve is to shut off the hot water going into the heater core.
Thanks for your great help!!!!!!

 

[Eleanor]

This stuff is cool! Thanks

 

[Nobody Cares]

Take off the console side panel . Look at the back of the heater / a/c control panel . That is where you will see the color coded vacuum hoses. Dave

 

[tgg901]

Take off the console side panel . Look at the back of the heater / a/c control panel . That is where you will see the color coded vacuum hoses. Dave

I see that what I can't see is the actuator. That's why I asked earlier if it's located on the drivers side. The area is so tight it's hard for me to focus. (Old fart with bad eyes) So I need to get my son to look for me and I want to give him a general location to start looking.
Thanks again! Tom

 

[tgg901]

Did you also see my question about the water shut off switch? Any comment or suggestions to that?
Tom

 

[Nobody Cares]

Did you try to follow the black vacuum hose with the BLUE stripe ?? That should lead to the right spot. Dave

 

[tgg901]

OK Dave this is what I just did:
Tested all hoses. They all held vacuum and opened actuators-doors.
Tested the vacuum from black hose and over 1 min. or so I had a constant vacuum of -18 in.
This was the first time I ever felt air from the defroster. (Testing Mode)
Replaced the switch.
Fixed and adjusted the switch for the water shut off valve.
And when I put it back together NO DEFROSTER. What are the possibilities that I bought a broken switch? Any other possibilities?
It seems like now of my repairs are ever simple
Thanks again for your help. Tom

 

[Yoda]

The Switch (Air/Heat/Defrost) has a grooved rubber (diaprham??) gasget on it. This directs the vacuum depending upon position of the switch.

This gasget could be shot, mis-aligned or deteriated to the point it doesn't work right any longer.

CAUTION if you take this apart, it is spring loaded and not fun to mess with don't ask me how I know

I mfr'd a keeper (plastic washer) piece for the levers, many moons ago and ended up taking the entire switch to my work bench and completely dis-assembly and re-assembled. The first attempt I had the grooved rubber diaprham in wrong. Once I got that straightened out... it's worked great since, nice and smooth and working in all positions.

The Assembly Manual was invaluable, a must have...

I say this, since you say the doors work until you reconnect the vacuum lines to the switch

Bud

 

[tgg901]

I put some vacuum on the actuators and they sure worked OK.
Do you think I have enough vacuum? How possible do you think it is that the new switch I purchased was also bad? Any instructions on how to test the switch?

Tom

 

[Nobody Cares]

If i remember correctly, i had to change the main vacuum line from ( i think on the engine side of the firewall ) to the switch. Bud is 100% correct on the switch. I also took mine apart and it was a real pain. Dave