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Hi guys,
First of all we are in Australia so don’t have the parts available at hand so require them to be posted.
The question I have is, when we finished rebuilding the 69 corvette we noticed the wipers didn’t work. I notice that there was no ground wire to the wiper motor so I ran one from the heater blower motor (which wasn’t working either - no ground). The Blower motor now works but the wipers only work when the washer button is pushed and then they go back to the park position as they should. I’m hoping someone can give me an answer if they have had the same problem. Is it a bad relay or no ground to the wiper switch? I wanted to ask the question first before pulling it apart again and chasing something that might be the wrong direction. Thanks in advance
Cameron
Last edited by Cameron Creek; Dec 31, 2017 at 12:17 AM.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Go to WILCOX's site. He posted the trouble shooting procedures there. GM alos posted a trouble shooting procedure as part of the AIM. It sounds like your switch might be a problem. I have a 68 and its a different enough system that I cant be of more help. Look for a wire diagram on his site as well as the vacuum schematics. If the door opens and it wipes I would say everything else seems to be in order other than the switch. It could be the override witch but I doubt it
page 8 under the "electrical components" describes the function of the system. start there and you can probably figure out what is working or how the system works
I believe the ground connection for both the heater/defroster motor and the wiper motor is at one of the starter mounting bolts.
The lead comes out of the engine harness rust before it gets to the starter.
Have you checked for that on your 69?
Thanks guys.
im going to bench test the motor today by placing 12v onto the yellow wire (#2) and ground wire to #1 (slow) then ground to wires #1 & #3 (Hi speed). The harness was previously butchered so ground wire was completely missing. If the motor doesn’t work after the bench test I will take a closer look at the switch and relay and see if they are missing a ground wire.
Thanks for the help - Cameron
Hi again,
I checked I had an earth at the relay and the switch - all seems ok. Wiper still didn’t work when switched so I pulled it off to bench test it. When I put 12V onto wiper supply and #2 terminal, and Grounded the wiper supply and #3 terminal it ran only just and very slow. Further investigation showed that the resistor appeared broken which proved to be so (didn’t measure 20.6 ohms).
This leads me to my question - will the faulty resistor cause the wiper motor to not run / run slowly? I didn’t want to order a new wiper motor if it is only a resistor problem.
See Photos Below
Thanks again - Cameron
Last edited by Cameron Creek; Jan 1, 2018 at 02:50 AM.
Yeah it is in the clockwise (on) position. The wiper only works when the washer is pushed (but only just and really slow). The wiper door limit switch is also in the correct position so there is 12v coming in on the red wire. A new ground has been ran from the heater/blower. I have checked the relay pulls in the contact when 12v is applied (also pulled it apart and re seated the contact with sand paper). Wiper switch appears to have a ground also.
I’m thinking if it isn’t the resistor then the motor has failed but thought I’d ask the question before purchasing a new one.Cheers 👍
Our harness was butchered beyond belief. There was no ground to the wiper at all and the heater blower ground didn’t work so I ran a new ground to both from the chassis. Heater blower now work fine but just have the wiper motor issue.Cheers Cameron
Last edited by Cameron Creek; Jan 1, 2018 at 07:01 AM.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Im guessing the previoius owner ran a direct live wire to your motor when it should have been a ground and fried it. My PO ran power direct to the motor and to the switch and when I tried it, the switch ended up melting. Call Willcox. He had a video on rebuilding the old motors. I dont know if he carries those parts in stock.
The wiper switches are terrible quality. You can take them apart carefully (remember where spring goes) and check the copper contact inside, I bough two new ones and used parts from them to rebuild original. I am surprised that they work as very flimsy. Also the connector only goes on one way. There are pictures of it installed correctly on site. Connector has obtrusion built in it so it goes one way.
You can test your resistor and replace if necessary. It should probably only affect the low setting and high should work.
Thanks again for your help. I ended up pulling the wiper motor apart. Removing the armature from the stator and cleaning it. The motor had sat for many year and had poor brush contact. The motor works fine now and has hi-low speeds.
On another note, we had fitted a brand new wiper arm vacuum switch to the wiper door and the door wouldn’t open or close by vacuum pressure. After further investigation it appears they are poor quality from new and leak vacuum so I will be ordering a new one from Willcox tomorrow so hopefully this will fix the vacuum problem and the wiper door operates properly.
69 wiper motor
