1972 Corvette Window Wiper Door
Thread Starter
Racer
Joined: Aug 2006
Posts: 363
Likes: 3
From: Norwalk Ca
1972 Corvette Window Wiper Door
Does anyone know why my windshield wiper door opens after I turn off the engine? Also, what is a fair price for a passenger side ignition wire shield? Any help would be appreciated. I posted under the General forum, but I figured that this is a better forum for my questions.
Drifting
Joined: Oct 2003
Posts: 1,426
Likes: 1
From: VetteMOD
St. Jude Donor '05-'07
I can't give you an answer but you might find it at:
www.corvettefaq.com
If I am not mistaken there is a vacuum system troubelshoot guide as well as a wealth of information on these cars.
www.corvettefaq.com
If I am not mistaken there is a vacuum system troubelshoot guide as well as a wealth of information on these cars.
Thread Starter
Racer
Joined: Aug 2006
Posts: 363
Likes: 3
From: Norwalk Ca
72 wiper door and headlights
I'm still confused. I've looked at the FAQ and just couldn't follow the vacuum diagrams. My wiper door and headlights all come up when I turn off the engine. The headlights will eventually close, but the wiper door stays open. Any help would be appreciated. I was wondering one thing, what do the check valves in the vacuum lines to the manifold do? Could one of these check valves be the cause of my problem?
Safety Car
Joined: Feb 2006
Posts: 3,557
Likes: 0
From: Ridgeway VA
Vacuum Lines
I have a '70 and solved recent problems.
First, check all vacuum lines for good fit -especially at carb
-Check under dash vacuum lines - especially solonoid that fits to
back of tach - check lines (hoses) and electrical connection.
- There is a relay that costs about $25 located under the RH
winshield wiper - it has a button on top - this was my problem
and I replaced it. (there is also a relay on the left hand side
which costs about $50)
I'm not an expert on the vacuum hoses but, reread the explanations
and diagrams then they will begin to make sense.
You might consider all new hoses which makes engine compartment
look nice also.
First, check all vacuum lines for good fit -especially at carb
-Check under dash vacuum lines - especially solonoid that fits to
back of tach - check lines (hoses) and electrical connection.
- There is a relay that costs about $25 located under the RH
winshield wiper - it has a button on top - this was my problem
and I replaced it. (there is also a relay on the left hand side
which costs about $50)
I'm not an expert on the vacuum hoses but, reread the explanations
and diagrams then they will begin to make sense.
You might consider all new hoses which makes engine compartment
look nice also.
Safety Car
Joined: Feb 2006
Posts: 3,557
Likes: 0
From: Ridgeway VA
Wiper Arm Shut off
I went through my notes and to be more specific - the wiper arm
control vacuum shut off valve which is located under the RH windshield
wiper is quite often the problem. This has a button on top when the
wipers come down it completes a circuit - it tells the door to close.
If it doesn't close then that could be the problem.
The solenoid changes an electrical signal from the wiper switch to
a vacuum signal to open the door. If it hisses, etc - it could be
the problem.
control vacuum shut off valve which is located under the RH windshield
wiper is quite often the problem. This has a button on top when the
wipers come down it completes a circuit - it tells the door to close.
If it doesn't close then that could be the problem.
The solenoid changes an electrical signal from the wiper switch to
a vacuum signal to open the door. If it hisses, etc - it could be
the problem.
Safety Car
Joined: Feb 2006
Posts: 3,557
Likes: 0
From: Ridgeway VA
Relay Pixs
I do not have pics of relays but go to Vette suppliers - Riks,
Eckers, etc - and search their sites for vacuum relays, etc, -
there you will see pics.
Also - there are relays under each headlite actuator - just make
sure hoses fit tight.
The vacuum canister for the wipers - here again, check hoses and
seals. (RH side in front of firewall.)
Under the LH fender is a vacuum tank - again check hoses.
If you have a bad hose,leaks, etc - you can get a replacement
at most auto stores. If an old hose doesn't want to come off -
cut it and put on the new.
This is a fun hobby - you get to learn alot. Good luck!
Eckers, etc - and search their sites for vacuum relays, etc, -
there you will see pics.
Also - there are relays under each headlite actuator - just make
sure hoses fit tight.
The vacuum canister for the wipers - here again, check hoses and
seals. (RH side in front of firewall.)
Under the LH fender is a vacuum tank - again check hoses.
If you have a bad hose,leaks, etc - you can get a replacement
at most auto stores. If an old hose doesn't want to come off -
cut it and put on the new.
This is a fun hobby - you get to learn alot. Good luck!
Melting Slicks
Joined: Mar 2005
Posts: 2,095
Likes: 299
From: Midlothian VA
USUALLY, when your headlights and wiper door rise/attempt to rise upon shutting off the motor it's because the vacuum check valve is bad.
It's cheap and easy to test and repair.
You will find the valve connected to the vacuum line coming out of the intake manifold just behind the carb.
It looks like a vacuum splitter as it has one port connected to the line coming out of the manifold but has two ports connecting to two smaller vac lines just behind it. It should be round and a brushed gray/silver color. Pull this valve out and check that it operates properly.
That is, it should only pass vacuum/air one direction. You can, of course, easily perform this test by blowing/sucking on either side of the valve. If it passes air/suction both ways then the valve is bad and needs replacing. You can get them from ZIP for @12.50
It's cheap and easy to test and repair.
You will find the valve connected to the vacuum line coming out of the intake manifold just behind the carb.
It looks like a vacuum splitter as it has one port connected to the line coming out of the manifold but has two ports connecting to two smaller vac lines just behind it. It should be round and a brushed gray/silver color. Pull this valve out and check that it operates properly.
That is, it should only pass vacuum/air one direction. You can, of course, easily perform this test by blowing/sucking on either side of the valve. If it passes air/suction both ways then the valve is bad and needs replacing. You can get them from ZIP for @12.50
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Melting Slicks
Joined: Aug 2002
Posts: 3,334
Likes: 4
From: Midland TX
Originally Posted by PETKAH
I went through my notes and to be more specific - the wiper arm
control vacuum shut off valve which is located under the RH windshield
wiper is quite often the problem. This has a button on top when the
wipers come down it completes a circuit - it tells the door to close.
If it doesn't close then that could be the problem.
The solenoid changes an electrical signal from the wiper switch to
a vacuum signal to open the door. If it hisses, etc - it could be
the problem.
control vacuum shut off valve which is located under the RH windshield
wiper is quite often the problem. This has a button on top when the
wipers come down it completes a circuit - it tells the door to close.
If it doesn't close then that could be the problem.
The solenoid changes an electrical signal from the wiper switch to
a vacuum signal to open the door. If it hisses, etc - it could be
the problem.
I removed the valve located under the RH wiper arm. It was worn out. In fact it came apart when I removed it. I replaced it with a new one and the wiper door works perfect.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Uhh....of course, natch....I had a similar problem, got a new check valve in spite of my old valce passing the suck test.....
and so I found the vacuum relays heeded taken apart and the spring modded so as not so much pressure, in other words lowering the manifold suck necessary to keep the relay from changing state and actuating the device, being headlights or wiper door, same thing....
beleive me, I tried all sorts of solutions/fixes before tearing into the relays...they were NEW relays....
dunno the final source of MY problem, just know that cutting about 1/3 of the spring length and re bending the cut end, and stretching it a bit solved the problem, sealed it up and re clamped the crimp ring, and it was fine for years.....just last winter I finally went to a linear actuator upon supply/suggestion from 69My way........
and so I found the vacuum relays heeded taken apart and the spring modded so as not so much pressure, in other words lowering the manifold suck necessary to keep the relay from changing state and actuating the device, being headlights or wiper door, same thing....
beleive me, I tried all sorts of solutions/fixes before tearing into the relays...they were NEW relays....
dunno the final source of MY problem, just know that cutting about 1/3 of the spring length and re bending the cut end, and stretching it a bit solved the problem, sealed it up and re clamped the crimp ring, and it was fine for years.....just last winter I finally went to a linear actuator upon supply/suggestion from 69My way........
Safety Car
Joined: Feb 2006
Posts: 3,557
Likes: 0
From: Ridgeway VA
Wiper Door Check Valve
It was about 6 months ago that I replaced the valve under the RH
wiper and everything worked fine until yesterday. Started the '70
and the wiper tray went up and stayed up. Checked on hoses, etc -
perhaps I need a check valve.
Just when you think you fixed something the mystery returns.
wiper and everything worked fine until yesterday. Started the '70
and the wiper tray went up and stayed up. Checked on hoses, etc -
perhaps I need a check valve.
Just when you think you fixed something the mystery returns.
Melting Slicks
Joined: Mar 2005
Posts: 2,095
Likes: 299
From: Midlothian VA
FYI:
The vacuum switch located under the RH/passenger wiper arm prevents the wiper door from closing before the wiper arms are parked.
It simply interrupts the vacuum signal going to the main wiper valve which should be located in the passenger wheel well. This is the same function that the electric wiper solenoid switch (behind the dash) and the wiper vacuum override switch (beneath the steering column) perform. Any of the three will cause the wiper door to operate, or not operate, as the case may be.
If your door opens upon starting the engine I'd check that any of these three aren't stuck (or as I've done in the past; simply forgot that I'd pulled the override switch below the column).
Additionally, should your vacuum circuit loose vacuum for whatever reason; your wiper door and headlights are designed to "fail" in the open position for safety reasons. So a loss of vacuum will cause your wiper door and headlights to open.
Info that should help in your troubleshooting efforts.
The vacuum switch located under the RH/passenger wiper arm prevents the wiper door from closing before the wiper arms are parked.
It simply interrupts the vacuum signal going to the main wiper valve which should be located in the passenger wheel well. This is the same function that the electric wiper solenoid switch (behind the dash) and the wiper vacuum override switch (beneath the steering column) perform. Any of the three will cause the wiper door to operate, or not operate, as the case may be.
If your door opens upon starting the engine I'd check that any of these three aren't stuck (or as I've done in the past; simply forgot that I'd pulled the override switch below the column).
Additionally, should your vacuum circuit loose vacuum for whatever reason; your wiper door and headlights are designed to "fail" in the open position for safety reasons. So a loss of vacuum will cause your wiper door and headlights to open.
Info that should help in your troubleshooting efforts.
Race Director
Joined: Oct 2008
Posts: 19,230
Likes: 1,672
From: Long Island
Mine seams to work but the wiper door stays open. The car is a work in progress, it's a 71.
I replaced the wiper arm switch which was bypassed. and have everything working up to the metal pipe .
thanks
Race Director
Joined: Oct 2008
Posts: 19,230
Likes: 1,672
From: Long Island
Unfortunately the check valve is good 
Used a hand vacuum pump to check.
The car came from a 80+ year old who had it for 30+ years and as I'm finding out really did not fix things just by passed them.
It's finally running semi ok, needs a carb, will do that after engine rebuild.
Will be pulling the dash pad this weekend to check the vacuum routing.
When comparing to my 72 there are 2 extra vac.
lines going into the firewall?
Used a hand vacuum pump to check.
The car came from a 80+ year old who had it for 30+ years and as I'm finding out really did not fix things just by passed them.
It's finally running semi ok, needs a carb, will do that after engine rebuild.
Will be pulling the dash pad this weekend to check the vacuum routing.
When comparing to my 72 there are 2 extra vac.
lines going into the firewall?
