Heater and Ac vacuum control
Thread Starter
1st Gear
Joined: Jun 2007
Posts: 1
Likes: 0
Heater and Ac vacuum control
Having a problem with the heater control switch. All of the electrical parts of the switch work great but the vacuum control wont open the vents or switch from the heater to the defrost. I have good vacuum coming into the control and just replaced the heater control unit but it still doesn't work. Is there something else to check like a valve or a damper dorr switch? Thanks!
Pro
Joined: Oct 2006
Posts: 545
Likes: 2
From: Peoplez Republik (communist portland) Orygun
OMG. I have been scouring the archives for this. Yes, please! Somebody help Dexter ASAP!
I have had the same darn problem with my 80. No defrost & no vent switching!
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
dexter551
Try pressing the 2 halves of the switch together.
I wrote this up awhile back for this problem.
The problem is that heater is the default position (no vac. or vac. leak) due to being designed in the north. Vent should be default. Very safe bet the problem is 1 OR 2:
1) The vac. line from engine is damaged from heat - a small plastic tube that goes in below the hood alarm switch into wiper valley. Replacing most of engine side w/ hose will fix. OR
2) The vac. switch itself is not switching due to vac. leak as the usually plastic rivet is not holding the 2 main switch parts together well. Besides replacing, it is also possible to tighten this &/or lube w/ a thin layer of white lithium grease or vasoline to fix.
3) If you have a heater, the small vac. tube to heater hose valve underhood probably also needs replacing. Block w/o heater.
PS The design problem comment is not intended to be offensive to any of our northern friends.
Try pressing the 2 halves of the switch together.
Originally Posted by Vette80regon
I have had the same darn problem with my 80. No defrost & no vent switching!
Originally Posted by tyler77
I have an 80 also with the same problem what up with this?
I wrote this up awhile back for this problem.
The problem is that heater is the default position (no vac. or vac. leak) due to being designed in the north. Vent should be default. Very safe bet the problem is 1 OR 2:
1) The vac. line from engine is damaged from heat - a small plastic tube that goes in below the hood alarm switch into wiper valley. Replacing most of engine side w/ hose will fix. OR
2) The vac. switch itself is not switching due to vac. leak as the usually plastic rivet is not holding the 2 main switch parts together well. Besides replacing, it is also possible to tighten this &/or lube w/ a thin layer of white lithium grease or vasoline to fix.
3) If you have a heater, the small vac. tube to heater hose valve underhood probably also needs replacing. Block w/o heater.
PS The design problem comment is not intended to be offensive to any of our northern friends.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Put your ear down to the selector lever - do you hear a hiss(vacuum leak)If you do the 2 halves have seperated.You can fix this but probably best to just buy a new one.
http://www.ecklers.com/product.asp?p...6&dept_id=1193
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Put your ear down to the selector lever - do you hear a hiss(vacuum leak)If you do the 2 halves have seperated.You can fix this but probably best to just buy a new one.
http://www.ecklers.com/product.asp?p...6&dept_id=1193
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Race Director
Joined: Jul 2002
Posts: 13,858
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From: A 12/8 man in a 4/4 world
using a hand vacuum, I tested all the lines.
1 made sure vacuum was present
2. moved all the parts by adding vacuum to the other lines.
I concluded that the vaccuum switch is inoperable.
Ill replace someday but it is low on my list.
1 made sure vacuum was present
2. moved all the parts by adding vacuum to the other lines.
I concluded that the vaccuum switch is inoperable.
Ill replace someday but it is low on my list.
Pro
Joined: May 2007
Posts: 593
Likes: 0
From: Warrenville IL
Haven't checked the heat on my new '75 yet but I can see one of the vaccum hoses in the engine compartment seems to have melted on itself. Likely to the point where the nothing can pass all the way through the hose. I'm sure I get good suck, but not to the other end!
How bad is it to change those hoses?
How bad is it to change those hoses?
Racer
Joined: Oct 2004
Posts: 258
Likes: 1
From: Wilkesboro NC
Put your ear down to the selector lever - do you hear a hiss(vacuum leak)If you do the 2 halves have seperated.You can fix this but probably best to just buy a new one.
http://www.ecklers.com/product.asp?p...6&dept_id=1193
Racer
Joined: Mar 2006
Posts: 366
Likes: 1
From: Houston Texas
Race Director
Joined: Jul 2002
Posts: 13,858
Likes: 0
From: A 12/8 man in a 4/4 world
Put your ear down to the selector lever - do you hear a hiss(vacuum leak)If you do the 2 halves have seperated.You can fix this but probably best to just buy a new one.
http://www.ecklers.com/product.asp?p...6&dept_id=1193
thanks for the site.
I thought I had to buy the whole assembly.
