1979 heater control problem
Thread Starter
2nd Gear
Joined: Mar 2007
Posts: 2
Likes: 0
1979 heater control problem
i have a 1979 corvette. the heater is stuck on the floor it will not move to vent or dash. i just rslpaced the heater core and still have the glove box out, all lines are back together. is there a trouble shoot guide any where.thank you
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
The mechanism that directs the flow is behind the guage cluster. Its the vaccum controlled part of the switch that activates it. I'll see if I can find a diagram.
Two threads with diagrams..
http://forums.corvetteforum.com/show...ontrol+diagram
http://forums.corvetteforum.com/show...ontrol+diagram
Jim
Two threads with diagrams..
http://forums.corvetteforum.com/show...ontrol+diagram
http://forums.corvetteforum.com/show...ontrol+diagram
Jim
Last edited by jdp6000; Mar 7, 2007 at 09:01 AM.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
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.
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.
