No air
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
On at least later C3 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.
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: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
In response to a PM.
The switch is in the console attached directly to the selector for Vent/(A/C)/Heat/Defog.
Some may be able to hear a leaking switch. A test can be done by removing a console side on your year model & pressing the switch together (engine running).
The switch is in the console attached directly to the selector for Vent/(A/C)/Heat/Defog.
Some may be able to hear a leaking switch. A test can be done by removing a console side on your year model & pressing the switch together (engine running).
