No defroster
Thread Starter
Burning Brakes
Joined: Jul 2007
Posts: 1,166
Likes: 284
From: Springfield MA
St. Jude Donor '10-'11-'12, '19, '21
No defroster
Posted this in another forum and got nothing.... Anyone here want to help me out?
>>>>>>>>>>>>>
Don't know if this has been covered or not, but here goes. My defroster is not working. When I push the slide lever from left to far right (defrost), nothing happenes. I mean the heat just keeps comming out on the floor. Nothing comes out of the top near the windshield. Nothing seems to be unhooked, or unattached. And there doesn't seem to be anything in the venting that would obstruct it. Did I miss something? Help!
Dave
>>>>>>>>>>>>>
Don't know if this has been covered or not, but here goes. My defroster is not working. When I push the slide lever from left to far right (defrost), nothing happenes. I mean the heat just keeps comming out on the floor. Nothing comes out of the top near the windshield. Nothing seems to be unhooked, or unattached. And there doesn't seem to be anything in the venting that would obstruct it. Did I miss something? Help!
Dave
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Posted this in another forum and got nothing.... Anyone here want to help me out?
>>>>>>>>>>>>>
Don't know if this has been covered or not, but here goes. My defroster is not working. When I push the slide lever from left to far right (defrost), nothing happenes. I mean the heat just keeps comming out on the floor. Nothing comes out of the top near the windshield. Nothing seems to be unhooked, or unattached. And there doesn't seem to be anything in the venting that would obstruct it. Did I miss something? Help!
Dave
>>>>>>>>>>>>>
Don't know if this has been covered or not, but here goes. My defroster is not working. When I push the slide lever from left to far right (defrost), nothing happenes. I mean the heat just keeps comming out on the floor. Nothing comes out of the top near the windshield. Nothing seems to be unhooked, or unattached. And there doesn't seem to be anything in the venting that would obstruct it. Did I miss something? Help!
Dave
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
This a link to what I think you need.
http://www.ecklers.com/product.asp?p...6&dept_id=1193
This is what i would check first but if you dont have vacuum at all to this valve the "default" is floor heat.Do you have air coming out of the vents?
http://www.ecklers.com/product.asp?p...6&dept_id=1193
This is what i would check first but if you dont have vacuum at all to this valve the "default" is floor heat.Do you have air coming out of the vents?
Last edited by ...Roger...; Sep 23, 2008 at 08:32 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The problem is either the rotary valve (on the side of the control head, inside the floor console or the plenum diverter door (in the heater ducting behind the gauge cluster). The rotary switch moves with the lever you mentioned; it directs vacuum to the proper path so that airflow goes where it should. The diverter door in the heater ducting may be frozen up or the vacuum actuator is not working (no signal or bad valve). If the airflow stays with the lower outlets...no matter what you do...you need to diagnose which of the above issues is your problem. Personally, I would rather dig into the lower console than the gauge cluster. I also think the odds of the diverter door being the problem is lower than the alternative [assuming it has worked correctly in the recent past]. The Chevrolet Service Manual shows the rotary valve circuit and which hoses go where. You want to test the line assigned to actuate the "Defrost" position to see if the diverter door works. Keep in mind, it could also be that the rotary switch isn't being 'moved' like it should be the control linkage. Good luck. 
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Been away on a family matter the past week, but I’ll see if I can help you some too!
The vacuum select switch is the normal failure point in the heater control. The center pin will break and the valve will come apart. This switch consist of two plastic maze like sections that when put together control the entire vacuum on the cars air conditioning system. This switch is located and controlled by the upper lever on your heater control and mounted with two screws to the control.
When new, the switch had a tiny bit of lubrication between the two halves. This lubrication also helped seal the switch. If the switch is together and not broken, you may try to force some white lithium in it. This may seal it up for you!
You can test the switch by using this chart below to guide you. This chart is listed under our repair help section on our web site.
Here is a picture of the part.
Here is a link the vacuum select switch. http://willcoxcorvette.com/product_i...ducts_id=12686
There is also another culprit that can be causing this problem! If you look a picture you will see what is called the defroster valve (actuator). This is controlled by the blue stripped hose that runs straight from the heater control to the heater box.
You may have a problem with this actuator!
Good luck,
Willcox
The vacuum select switch is the normal failure point in the heater control. The center pin will break and the valve will come apart. This switch consist of two plastic maze like sections that when put together control the entire vacuum on the cars air conditioning system. This switch is located and controlled by the upper lever on your heater control and mounted with two screws to the control.
When new, the switch had a tiny bit of lubrication between the two halves. This lubrication also helped seal the switch. If the switch is together and not broken, you may try to force some white lithium in it. This may seal it up for you!
You can test the switch by using this chart below to guide you. This chart is listed under our repair help section on our web site.
Here is a picture of the part.
Here is a link the vacuum select switch. http://willcoxcorvette.com/product_i...ducts_id=12686
There is also another culprit that can be causing this problem! If you look a picture you will see what is called the defroster valve (actuator). This is controlled by the blue stripped hose that runs straight from the heater control to the heater box.
You may have a problem with this actuator!
Good luck,
Willcox
Thread Starter
Burning Brakes
Joined: Jul 2007
Posts: 1,166
Likes: 284
From: Springfield MA
St. Jude Donor '10-'11-'12, '19, '21
When I slide the heater/defroster switch from off to the defrost position there doesn't seem to be any resistance. I can't remember if there ever was. Should there be a little pull on the slide when you move it?
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Safety Car
Joined: Oct 2005
Posts: 3,570
Likes: 1
From: Algonac Michigan
I'm thinking that due to the fact that the diverter is vac. operated,only a slight amount of resistance should be felt.
Thread Starter
Burning Brakes
Joined: Jul 2007
Posts: 1,166
Likes: 284
From: Springfield MA
St. Jude Donor '10-'11-'12, '19, '21
Thanks for all the help so far. I'll post the out come later this week.
This is by far one of the most helpful forums out there. Thanks!
Dave
This is by far one of the most helpful forums out there. Thanks!
Dave
Thread Starter
Burning Brakes
Joined: Jul 2007
Posts: 1,166
Likes: 284
From: Springfield MA
St. Jude Donor '10-'11-'12, '19, '21
It was the vacumn switch that Wilcox mentioned. It seems that Buba was into the heater, while he was screwing with so many other things. Oh well, got it fixed for now with a new screw to hold it together. Will have to order the part to make a permanant fix. Thanks to everybody for the suggestions and the help.
Dave
Dave
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Dave,
Good news! If you put it back together with a screw with some lube in between the two sections you probably won't need a new one! (and you have to give credit to the other guys too, they were spot on. . . DWncchs and 7t1vette).
This is a common problem with this heater control assembly and not just in Corvettes.
When this part was on national backorder over a year ago, we did the same thing in our shop as a temporary fix for a customer. We used a small screw with a plastic locking nut and a couple of washers. Combined with the factory spring it worked great.
This was over a year ago and the car was in the shop last week. . . The thing is still working fine.
The part had a plastic rivet in it that held it together, when they get old, the rivet will break and allow vacuum to leak. (Your car is probably running better now too).
Willcox Inc.
Good news! If you put it back together with a screw with some lube in between the two sections you probably won't need a new one! (and you have to give credit to the other guys too, they were spot on. . . DWncchs and 7t1vette).
This is a common problem with this heater control assembly and not just in Corvettes.
When this part was on national backorder over a year ago, we did the same thing in our shop as a temporary fix for a customer. We used a small screw with a plastic locking nut and a couple of washers. Combined with the factory spring it worked great.
This was over a year ago and the car was in the shop last week. . . The thing is still working fine.
The part had a plastic rivet in it that held it together, when they get old, the rivet will break and allow vacuum to leak. (Your car is probably running better now too).
Willcox Inc.
