C3 Windshield Wiper issues
Melting Slicks
Joined: Mar 2002
Posts: 2,526
Likes: 104
From: Stafford Va
The limit switch at the firewall is depressed when the door opens. If you don't have the door there is nothing there to depress the plunger.
The vacuum system has very little to do with the motor function aside from this plunger. On a normal car when you turn on the wipers, ground is sent to the tach solenoid on the back of the tach. When this happens vacuum is blocked to the relay and in turn, the actuator pulls the door open. When the door opens the plunger on the door linkage press's on the limit switch, which then allows 12 volts to pass to the motor on the red/white wire.
Willcox
The vacuum system has very little to do with the motor function aside from this plunger. On a normal car when you turn on the wipers, ground is sent to the tach solenoid on the back of the tach. When this happens vacuum is blocked to the relay and in turn, the actuator pulls the door open. When the door opens the plunger on the door linkage press's on the limit switch, which then allows 12 volts to pass to the motor on the red/white wire.
Willcox
kevin
Last edited by vstol; Mar 5, 2015 at 11:22 AM.
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
Jumper the limit switch if you don't have the plunger.
The tach solenoid operates like this: When you turn your wipers on power is on the yellow wire to the solenoid. When the solenoid is powered up it blocks the vacuum on hose "H" which blocks the vacuum on G and 10... When this happens the relay plunger drops (because vacuum is blocked), it drops and changes vacuum position on 6 and 9 which makes the door open up.
Make sense? If not post back again.
Willcox
How the relay operates:
The tach solenoid operates like this: When you turn your wipers on power is on the yellow wire to the solenoid. When the solenoid is powered up it blocks the vacuum on hose "H" which blocks the vacuum on G and 10... When this happens the relay plunger drops (because vacuum is blocked), it drops and changes vacuum position on 6 and 9 which makes the door open up.
Make sense? If not post back again.
Willcox
How the relay operates:
Melting Slicks
Joined: Mar 2002
Posts: 2,526
Likes: 104
From: Stafford Va
Jumper the limit switch if you don't have the plunger.
The tach solenoid operates like this: When you turn your wipers on power is on the yellow wire to the solenoid. When the solenoid is powered up it blocks the vacuum on hose "H" which blocks the vacuum on G and 10... When this happens the relay plunger drops (because vacuum is blocked), it drops and changes vacuum position on 6 and 9 which makes the door open up.
Make sense? If not post back again.
Willcox
How the relay operates:
The tach solenoid operates like this: When you turn your wipers on power is on the yellow wire to the solenoid. When the solenoid is powered up it blocks the vacuum on hose "H" which blocks the vacuum on G and 10... When this happens the relay plunger drops (because vacuum is blocked), it drops and changes vacuum position on 6 and 9 which makes the door open up.
Make sense? If not post back again.
Willcox
How the relay operates:
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
If you are trying to eliminate the over-ride switch and the relay then wire the car up like a 73-76 wiper motor...
Willcox
Willcox
Last edited by Willcox Corvette; Mar 6, 2015 at 08:52 AM.
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Melting Slicks
Joined: Mar 2002
Posts: 2,526
Likes: 104
From: Stafford Va
Thanks for the help but my grey matter does not follow the above diagram. I will be using a aftermarket wiring harness and switch which might have a bearing on why I am not following the schematic. That said many thanks for the try.
Just watched one of your videos and I think I got it, it sucks to get older.
Kevin
https://www.corvetteforum.com/forums...ica-kinda.html
Just watched one of your videos and I think I got it, it sucks to get older.
Kevin
https://www.corvetteforum.com/forums...ica-kinda.html
Last edited by vstol; Mar 10, 2015 at 02:56 PM.
Intermediate
Joined: Oct 2015
Posts: 35
Likes: 1
1968 with over ride light on. Wiper system does not work, disconnect the connector (black/red/white sires) to the motor. Override light goes off and I can use the wiper door vacuum override to open and close the door. The electrical override switch seems to be working as designed. Plug the connector back in and the over ride light comes on and door closes. Short in the wiper motor?? It's only a month old, got it from Eckler's. Did not have the problem before I did the water pump, may just be coincidence... Thoughts?? Thank you in advance.
Intermediate
Joined: Oct 2015
Posts: 35
Likes: 1
Okay, After chasing down the wires, here's what I got. The limit switch doesn't seem to be depress enough. Maybe the tip of it rubbed down over the years, some times it works, some times it doesn't. Either way, when I tested it earlier this week, I used my finger, so it went down lower than the bracket holding it. Today, I was trying to use the bolt that's secured to the wiper door rails/hinges. That's a big piece of metal, so it's stop at the limit switch bracket, the button itself doesn't go any lower. After using my finger and screw driver to push it further in, everything went back to normal. So for the temp fix, I glued a little gasket material to tip of the limit switch, so far so good. Everything is working for now. If this pose is a little unclear, feel free to ask me any questions.