Wiper cowl
Thread Starter
7th Gear
Joined: Jul 2014
Posts: 7
Likes: 0
Wiper cowl
1970 with vacuum actuated wiper cowl. Cowl will not open. Replaced Actuator, still doesn't open. Has vacuum to keep it closed. No vacuum to open when wiper switch is activated. Vacuum to keep it closed is deactivated when switch is activated. Any ideas?
Team Owner
Joined: Sep 2006
Posts: 31,200
Likes: 4,287
From: Westminster Maryland
Hi c47.
The wiper door and wipers can be a bit of a puzzle on occasion.
Have you had the door opening and closing before the problem occurred that made you replace the actuator?
Did you get the red and green striped hose back on the actuator in the correct place?
Are you sure the hose to and from the wiper door relay are connected at the proper ports?
Have you tried using the wiper door vacuum override switch below the steering column to open the door? It's the one on the right. It opens and closes the door without using the wiper switch.
Regards,
Alan
Pull Down to Open Wiper Door.
The wiper door and wipers can be a bit of a puzzle on occasion.
Have you had the door opening and closing before the problem occurred that made you replace the actuator?
Did you get the red and green striped hose back on the actuator in the correct place?
Are you sure the hose to and from the wiper door relay are connected at the proper ports?
Have you tried using the wiper door vacuum override switch below the steering column to open the door? It's the one on the right. It opens and closes the door without using the wiper switch.
Regards,
Alan
Pull Down to Open Wiper Door.
Last edited by Alan 71; Nov 12, 2016 at 11:28 AM.
Racer
Joined: Feb 2016
Posts: 488
Likes: 43
From: Vancouver British Columbia
One is an Assembly manual, (not expensive) $25 at Wilcox
Two, a mityvac (also not expensive) about $40 bucks at harbour freight
Then just hook it up to either side of your vacuum actuator pot and watch what does and does not work. Then work backwards to either chase the vacuum leak or move forward to a wiper door linkage problem.
Good Luck! Pete
Team Owner
Joined: Sep 2006
Posts: 31,200
Likes: 4,287
From: Westminster Maryland
Hi V71,
I agree and will add 1 more item… a trouble shooting guide like the one from Dr.Rebuild that helps you test each component individually, using a pump like the Mityvac Dave mentions, to see if it's operating as it should be.
Because the system is a bit of a mystery the temptation is to begin replacing parts until you happen to replace the one that's not working…. this becomes expensive and frustrating too quickly!
Regards,
Alan
I agree and will add 1 more item… a trouble shooting guide like the one from Dr.Rebuild that helps you test each component individually, using a pump like the Mityvac Dave mentions, to see if it's operating as it should be.
Because the system is a bit of a mystery the temptation is to begin replacing parts until you happen to replace the one that's not working…. this becomes expensive and frustrating too quickly!
Regards,
Alan
Safety Car
Joined: May 2001
Posts: 4,747
Likes: 1,642
From: Fairfax Virginia
One more tool to add to the list....
I would like to suggest another tool that every Corvette owner could benefit from owning.
The "POWER PROBE", this tool connects to your battery directly and you can supply +12 VDC or 0 VDC at the tip by simply holding a button in. The Power probe also has a built in 20 amp breaker to make it safer.
I have two of these gadgets so I can always find at least one.
They just introduced a new model that gives you even more functions. I still use the first generation on both my Corvettes, in fact it sits right next to my Fluke multi-meter in my "Corvette" tool box. I would not want to be without one of these. I have used it on aircraft, boats, motorcycles and cars and to me it is virtually "priceless".
The "POWER PROBE", this tool connects to your battery directly and you can supply +12 VDC or 0 VDC at the tip by simply holding a button in. The Power probe also has a built in 20 amp breaker to make it safer.
I have two of these gadgets so I can always find at least one.
They just introduced a new model that gives you even more functions. I still use the first generation on both my Corvettes, in fact it sits right next to my Fluke multi-meter in my "Corvette" tool box. I would not want to be without one of these. I have used it on aircraft, boats, motorcycles and cars and to me it is virtually "priceless".
Thread Starter
7th Gear
Joined: Jul 2014
Posts: 7
Likes: 0
Alan:
Wiper door has not worked since I purchased the car three years ago. Override switch does not open cowl. (Headlight override does work.)
Hooked up new actuator same as original.
Wiper door has not worked since I purchased the car three years ago. Override switch does not open cowl. (Headlight override does work.)
Hooked up new actuator same as original.
Hi c47.
The wiper door and wipers can be a bit of a puzzle on occasion.
Have you had the door opening and closing before the problem occurred that made you replace the actuator?
Did you get the red and green striped hose back on the actuator in the correct place?
Are you sure the hose to and from the wiper door relay are connected at the proper ports?
Have you tried using the wiper door vacuum override switch below the steering column to open the door? It's the one on the right. It opens and closes the door without using the wiper switch.
Regards,
Alan
Pull Down to Open Wiper Door.
The wiper door and wipers can be a bit of a puzzle on occasion.
Have you had the door opening and closing before the problem occurred that made you replace the actuator?
Did you get the red and green striped hose back on the actuator in the correct place?
Are you sure the hose to and from the wiper door relay are connected at the proper ports?
Have you tried using the wiper door vacuum override switch below the steering column to open the door? It's the one on the right. It opens and closes the door without using the wiper switch.
Regards,
Alan
Pull Down to Open Wiper Door.
Thread Starter
7th Gear
Joined: Jul 2014
Posts: 7
Likes: 0
I have the assembly manual, but don''t find it very useful for this problem. I have applied suction to each of the vacuum hookups of the pot and the pot activates like it should. Can't find a leak in the vacuum lines, but not sure one of the lines isn't leaking somewhere.
QUOTE=VancouverL71;1593460953]
Having little to no experience a year ago, I quickly realized that there are two things you will need on the old corvette if you plan to do your own work.
One is an Assembly manual, (not expensive) $25 at Wilcox
Two, a mityvac (also not expensive) about $40 bucks at harbour freight
Then just hook it up to either side of your vacuum actuator pot and watch what does and does not work. Then work backwards to either chase the vacuum leak or move forward to a wiper door linkage problem.
Good Luck! Pete[/QUOTE]
QUOTE=VancouverL71;1593460953]
Having little to no experience a year ago, I quickly realized that there are two things you will need on the old corvette if you plan to do your own work.
One is an Assembly manual, (not expensive) $25 at Wilcox
Two, a mityvac (also not expensive) about $40 bucks at harbour freight
Then just hook it up to either side of your vacuum actuator pot and watch what does and does not work. Then work backwards to either chase the vacuum leak or move forward to a wiper door linkage problem.
Good Luck! Pete[/QUOTE]
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Team Owner
Joined: Sep 2006
Posts: 31,200
Likes: 4,287
From: Westminster Maryland
Hi c,
In addition to the wiper door actuator there other components that will need to be checked….the wiper door relay (likely mounted on the firewall on your 70), the wiper door 3 port interlock switch (in the wiper bay under the right side wiper transmission), and the wiper door solenoid valve switch (mounted behind the tach).
These will all need to be tested in sequence.
Take Dave up on his offer to help you through the tests.
Send him a pm if he doesn't return to this thread.
Regards,
Alan
In addition to the wiper door actuator there other components that will need to be checked….the wiper door relay (likely mounted on the firewall on your 70), the wiper door 3 port interlock switch (in the wiper bay under the right side wiper transmission), and the wiper door solenoid valve switch (mounted behind the tach).
These will all need to be tested in sequence.
Take Dave up on his offer to help you through the tests.
Send him a pm if he doesn't return to this thread.
Regards,
Alan