A/C Woes
Thread Starter
Instructor
Joined: Jul 2005
Posts: 124
Likes: 0
A/C Woes
When I turn on my A/C, I can feel cold air coming out of the foot outlets. But no air comes out of the other outlets at all.
I took out the glove box pocket to check that the tubing was not disconnected from the blower casing. It seems coupled OK.
(The only thing is a gap between the windshield defrost air duct and the large air duct behnd the gauge console. That's another topic, but I'll address later, but no air is coming out of that gap either.)
Why would air come out the foot outlets but not elsewhere? What could I check first?
Thanks
I took out the glove box pocket to check that the tubing was not disconnected from the blower casing. It seems coupled OK.
(The only thing is a gap between the windshield defrost air duct and the large air duct behnd the gauge console. That's another topic, but I'll address later, but no air is coming out of that gap either.)
Why would air come out the foot outlets but not elsewhere? What could I check first?
Thanks
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
The air is not being diverted. Also, that gap is on all Vettes, and the factory duct tape has fallen off. Simply wrap a new length of duct tape around it.
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.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 124
Likes: 0
Hmm, I took out the shifter console a couple of weeks ago to repaint the cigarette lighter lid. Maybe I did not connect something right back? I had not tried to use the A/C until now since then.
So there's a vacuum line from the engine going to the A/C control panel? Where's the vac. switch?
So there's a vacuum line from the engine going to the A/C control panel? Where's the vac. switch?
Drifting
Joined: Sep 2007
Posts: 1,572
Likes: 51
From: Wichita Kansas
Your vacume actuators are not shifting the vents. As mentioned your vacume lines need to be checked. Take a look at the 3 lines that come through the firewall behind the glove box. If they need replaced they will slide through that gromet. The rigging from the selector to the valve behind the glove box needs to be checked and adjusted. The adjustment is in the cable jacket at the right side of the console and sometimes under the edge of the carpet. This is the common problem for no air in the upper vents.
Make sure the valve plunger (behind the glove box) is completly pressed in when you slide the temp comtrol.
At the controls in the console the vacume selector valve can be seperated from the unit. This rotory valve ports vacume and becomes loose from the plastic rivit. The rivit can be replaced with a fat short screw. I have replace a few of them and was able to retain the tensioner washer under the screw.
As mentioned use a little lube on the rubber portions of the rotory valve when seperated. I just use vaseoline.
Once you remove the glove box and see how the system works it is very easy to repair. The plenium needs to be resealed with duct tape.
Make sure the valve plunger (behind the glove box) is completly pressed in when you slide the temp comtrol.
At the controls in the console the vacume selector valve can be seperated from the unit. This rotory valve ports vacume and becomes loose from the plastic rivit. The rivit can be replaced with a fat short screw. I have replace a few of them and was able to retain the tensioner washer under the screw.
As mentioned use a little lube on the rubber portions of the rotory valve when seperated. I just use vaseoline.
Once you remove the glove box and see how the system works it is very easy to repair. The plenium needs to be resealed with duct tape.
Last edited by Aggitated Monkey; Mar 28, 2008 at 10:07 AM.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
So there's a vacuum line from the engine going to the A/C control panel? Where's the vac. switch?
The switch is underneath the console connected directly to the Vent/ A/C selector control.
