A Third Vacum Override?
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Joined: Feb 2017
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From: Lewes Delaware
A Third Vacum Override?
CF Nation, I have been asked to take a crack at a 1971 vacum issue they were having. As usual, they had replaced a bunch of relays, switches, and actuators prior to them calling me....so I walk in and find what looked to be the typical vacum layout until I looked under the dash and saw a 3rd override pull switch under the hood release lever??
The issue I'm having is the red line small line which attaches to a hardline behind motor and then goes into firewall isn't getting any vacum, I believe this is caused by a faulty selonoid behind the tach however because of the 3rd override, and a tiny tiny hose being apart of the system...I'm not sure what the issue is!
Can anyone help me out? I'm looking for the function of the 3rd override, and if there is something I should do to know for sure if the solenoid is bad.
The headlights are working, my issue is all about the wipers...Thanks!!
The issue I'm having is the red line small line which attaches to a hardline behind motor and then goes into firewall isn't getting any vacum, I believe this is caused by a faulty selonoid behind the tach however because of the 3rd override, and a tiny tiny hose being apart of the system...I'm not sure what the issue is!
Can anyone help me out? I'm looking for the function of the 3rd override, and if there is something I should do to know for sure if the solenoid is bad.
The headlights are working, my issue is all about the wipers...Thanks!!
Safety Car
Joined: Oct 2007
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From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
71 C3 only has 2 vacuum override switches, 1 for lights, 1 for wiper door.
your third is a bubba switch.
the solenoid behind the tach. is wiper door open vacuum solenoid.
the solenoid receives it's electrical signal, from the wiper motor running contacts.
your third is a bubba switch.
the solenoid behind the tach. is wiper door open vacuum solenoid.
the solenoid receives it's electrical signal, from the wiper motor running contacts.
Last edited by 69Vett; May 12, 2017 at 05:02 PM.
Team Owner
Joined: Sep 2006
Posts: 31,273
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From: Westminster Maryland
Hi D,
Is this the red striped hose you're referring to?
If so, it runs to the wiper door 3 port interlock switch that's mounted in the wiper bay near the right side wiper transmission.
Regards,
Alan
Is this the red striped hose you're referring to?
If so, it runs to the wiper door 3 port interlock switch that's mounted in the wiper bay near the right side wiper transmission.
Regards,
Alan
Last edited by Alan 71; May 12, 2017 at 05:55 PM.
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Joined: Feb 2017
Posts: 69
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From: Lewes Delaware
By the way....your engine bay is gorgeous!! I thought my bay looked good, but yours looks fresh off the line...Alan you are my inspiration to get my bay looking better!
Team Owner
Joined: Sep 2006
Posts: 31,273
Likes: 4,366
From: Westminster Maryland
Hi D,
Let me know how how things work out.
I think your engine and compartment look terrific!
It shows such nice attention to detail that is so is lacking in many folks work.
I have always liked the look of the sb engines…. and I guess especially those with painted intake manifolds and valve covers.
Again nice work!
Regards,
Alan
Let me know how how things work out.
I think your engine and compartment look terrific!
It shows such nice attention to detail that is so is lacking in many folks work.
I have always liked the look of the sb engines…. and I guess especially those with painted intake manifolds and valve covers.
Again nice work!
Regards,
Alan
Drifting
Joined: Jul 2006
Posts: 1,259
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From: Deplorableville Nebraska
Sounds like Bubba has given the car a visit. There should not be 3 override switches. For a good description of what the solenoid is supposed to do and a good way to test it with a Mityvac while it's in the car, refer to this post;
https://www.corvetteforum.com/forums...-question.html
Give post 71 a good look. Another common mistake is for the vacuum hoses leading to the wiper door override to be switched. The hose from the solenoid needs to be installed on the port closest to the pull down **** on the override switch. If switched, door will not work.
https://www.corvetteforum.com/forums...-question.html
Give post 71 a good look. Another common mistake is for the vacuum hoses leading to the wiper door override to be switched. The hose from the solenoid needs to be installed on the port closest to the pull down **** on the override switch. If switched, door will not work.
Thread Starter
Advanced
Joined: Feb 2017
Posts: 69
Likes: 14
From: Lewes Delaware
Sounds like Bubba has given the car a visit. There should not be 3 override switches. For a good description of what the solenoid is supposed to do and a good way to test it with a Mityvac while it's in the car, refer to this post;
https://www.corvetteforum.com/forums...-question.html
Give post 71 a good look. Another common mistake is for the vacuum hoses leading to the wiper door override to be switched. The hose from the solenoid needs to be installed on the port closest to the pull down **** on the override switch. If switched, door will not work.
https://www.corvetteforum.com/forums...-question.html
Give post 71 a good look. Another common mistake is for the vacuum hoses leading to the wiper door override to be switched. The hose from the solenoid needs to be installed on the port closest to the pull down **** on the override switch. If switched, door will not work.
Dave, I think I will first begin by removing the bubba work and then test the solenoid as described...Thanks for the expertise! As usual you guys come through...more to follow!
