wiper override switch
Thread Starter
Drifting
Joined: Jul 2015
Posts: 1,765
Likes: 254
From: Catlett VA
wiper override switch
I just finished a frustrating couple of weeks sorting out why my power curve died at 4800 rpm after switching to aluminum heads on my 68 convert with NOM 454. After going thru fuel, carb, ignition possible problems I found the machine shop which assembled the valves had the installed closed seat spring height off by 0.225 inch (too tall). This decreased the spring pressure to the point that I got valve float. I installed new/stiffer valve springs, carefully checked installed height and finally got the problem solved...................only to have another problem crop up. Now my wipers- which worked properly- did not work. Long story short- sometime during working on the car I bumped the wiper override switch. I confirmed it this morning- when the battery was dead from the current drain. I now have the !@#$%^& switch duct taped in the off position.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You likely have a cracked switch that is now leaking vacuum (or, sucking air, if you prefer). You just need to bypass the valve to verify that sending vacuum to the proper hose WILL open the wiper door. It is still possible that the 'bump' just happened at the same time as when another 'fault' in that system occurred. [Maybe a vacuum line came off from above at the same time you bumped the switch.]
It is just best to check out the system and verify that 1) the switch really is the problem and 2) replacing the switch really will fix the problem.
It is just best to check out the system and verify that 1) the switch really is the problem and 2) replacing the switch really will fix the problem.
Le Mans Master
Joined: May 2003
Posts: 8,878
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From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
You likely have a cracked switch that is now leaking vacuum (or, sucking air, if you prefer). You just need to bypass the valve to verify that sending vacuum to the proper hose WILL open the wiper door. It is still possible that the 'bump' just happened at the same time as when another 'fault' in that system occurred. [Maybe a vacuum line came off from above at the same time you bumped the switch.]
It is just best to check out the system and verify that 1) the switch really is the problem and 2) replacing the switch really will fix the problem.
It is just best to check out the system and verify that 1) the switch really is the problem and 2) replacing the switch really will fix the problem.
Thread Starter
Drifting
Joined: Jul 2015
Posts: 1,765
Likes: 254
From: Catlett VA
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
just put a dot of white paint where you can see it when its off. you'll be able to see the position at a glance. you could also remove the **** and put a nylon washer on the switch then replace the **** creating enough friction that it cant be bumped on.
Congrats on solving the valve float, I don't think I would have figured that out
Congrats on solving the valve float, I don't think I would have figured that out
Thread Starter
Drifting
Joined: Jul 2015
Posts: 1,765
Likes: 254
From: Catlett VA
wiper override switch
just put a dot of white paint where you can see it when its off. you'll be able to see the position at a glance. you could also remove the **** and put a nylon washer on the switch then replace the **** creating enough friction that it cant be bumped on.
Congrats on solving the valve float, I don't think I would have figured that out
Congrats on solving the valve float, I don't think I would have figured that out
Thanks for the suggestions on the switch. I will definitely put the white dot there to show its position. I may have to modify the switch to add tension. The original switch did not work at all and the replacement switch I bought has such a weak set screw on the plastic **** it barely supports the weight of the ****. It fell off once and was lying on the carpet. I may cross drill the hole and put a threaded screw in place.
I can't really take credit for solving the valve float problem. The installed spring height was real low on my list of suspected problems and I got to it only after exhausting all of the other issues. I bought the heads and had the valves installed by a well-established large engine builder in CA. Didn't think I needed to double check their work. ajrothm on the forum diagnosed the problem early on and deserves the credit. So, when I started following his advise, it all worked out.
Thread Starter
Drifting
Joined: Jul 2015
Posts: 1,765
Likes: 254
From: Catlett VA
Thanks, but I have previously replaced the switch and with it now in the correct off position, the wipers work. All of the vacuum tubing, wiper door, etc. was removed by the PO and are replaced by a long style hood with no need for the vacuum system.
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Ron- I'd be in line to pull that trigger.. lol.. 
Be glad you have an early car because the late one with the light is even more of a PITA. Either way, if that switch is in the on position it'll kill a battery pretty quick.
Be glad you have an early car because the late one with the light is even more of a PITA. Either way, if that switch is in the on position it'll kill a battery pretty quick.
Thread Starter
Drifting
Joined: Jul 2015
Posts: 1,765
Likes: 254
From: Catlett VA
Does the indicator light say "Dummy, turn off the switch"? JK