Hey Y'all, Just got my first 1981 C3 corvette a few weeks ago and am excited to be working on it. Unfortunately I can't figure out why my windshield wipers wont turn off, the only way they turn off is when I unplug the single wire to the motor. I took out the switch to see if there were problems with it and it seems fine on the inside and the windshield wipers still dont turn off even with the switch out. When the switch is in you can change the speed and delay of the wipers but never turn them off. there is also a noise coming from behind the driver side seat where the battery is everytime it "switches".
Any advice would be greatly appreciated, also if anyone has a wiring diagram for the windshield wipers that would also be a big help!
Side Note: used a volt tester with the switch out and could only get power the the Pinkish red wire (F), not sure if that how its supposed to be just trying to give enough information.

Thanks,
Adam

 

The motor has a grounding problem. To park them, take a piece of wire and touch it from the wiper motor body to a good ground source on the engine. They will park, then you can locate your faulty ground.
Cheers, Greg

 

Thanks for the advice Greg. Just spent the last couple hours messing around with them and trying the ground solution. Nothing's changed, although now the wipers just seem to go one constant speed.
This is what I got so far:
-Power is getting to the motor and only stops when the 3 or single prong connection is unplugged,
-The switch seems to have no effect on the wipers except the washer motor
-Tried putting a wire to the wiper motor and a good ground source and still didn't stop the wipers

 

Something to try,
With the wiper switch in the OFF position, put a little pressure down on the switch **** and see if the wiper motor parks...
Here is a good document from Willcox Corvette about how to clean the circuit rails of the wiper switch
http://repairs.willcoxcorvette.com/w...tch-repair.pdf

 

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https://www.corvetteforum.com/forums...uestion-7.html

@bmotojoe also helped me..
Wasn’t my tach problem but mine would not shut off either and is fixable..play with switch as suggested betting that cog is worn..

 

Can't believe that was over a year ago...
How Time Fly's

 

Not sure if you've checked this: On earlier models (C2 and early C3), the switch grounds the motor in different configurations; it may be the same for lateC3s. Check to make sure the switch itself is grounded.

 

I gave this a try and it worked! Just a little bit of pressure and they parked. They only seem to park after each time I put a bit of pressure. Gonna try cleaning them up and seeing if that'll help with the speed/delay of the wipers as well as make it so I won't have to keep putting a bit of pressure to get them to park each time.

Thanks for the help!

 

then i bet it is as i posted above.. that plastic has to disengage to power ...
cleaning did not fix mine.. be curious as to what you find

 

@bmotojoe @interpon

Welp! It works.... to an extent LOL!
When I took it apart I noticed that the copper rail was bent a little lifting it up right where the plastic node is, so i'm assuming it was just lifted enough to the point where it wouldn't connect. I also noticed that where the copper connects to the wire connection, it was lifting up so i'm guessing every time someone went to plug it in it would push it up, lifting the entire copper rail. So I fixed all that and cleaned and greased and threw it back in the car.

Now, it turns off which is good. But now when its on, the wipers are all a constant speed no matter where on the switch except off, and when the switch is at the top it now turns the washer motor on too as well as the constant wiper.

 

did that too.. pulled twice.. any close pics of the nodes? look very closely ..they all should protrude the same amount..pics?
there is also a bb in there.. is it still there?

 

It's sounds like you are headed in the right direction
Little better understanding of how the wiper switch alone sends grounds to the wiper motors park switch.
OFF Circuits #150 & #91 Connected
LOW SPEED Circuits #150 - #91 - #92 Connected
HIGH SPEED Circuits #150 & #92 Connected.
Circuit #93 is ignition on 12vdc
I know you have a delay controller in your 81 and it may use different circuit numbers but the same Wiper Motor Park switch was used from 1975-1982
When Circuits #150 #91 & #92 are connected the solenoid of the park switch energizes.
The solenoid will retract the paw of the park switch closing a set of contacts passing voltage through the 40ohm resistor and through the wiper motor shunt field windings.
When you turn your wiper switch to the OFF position, the switch should drop Circuit #92 de-energizing the solenoid extending the paw but because the internal contacts are still made (latched) until the wiper motor comes to a complete rest it's only then the contacts open and voltage through shunt field windings of the motor stops.
So my guess is once you select LOW speed or HIGH speed and you turn the wiper switch to OFF Circuit #92 is not dropping out of the loop, not de-energizing park switch solenoid, not retracting paw, not opening contacts...
Wiper Motor Continues to run...
I will add HIGH SPEED, Circuits #150 & #92 solenoid still energizes but bypasses 40ohm resistor and is a direct path to motor Series Field windings.

 

Should there be 2 wires going into A?



Here are some pics, hopfully they help. And yes the bb and spring are still in there.

 

I believe I understand what your saying to an extent haha! How and what would be the best way to test and fix that though? Would you suggest I take apart the motor?

 

No don't take the motor apart, I truly believe the problem is your switch.
Before you took the switch apart you had both LOW and HIGH speeds but wiper motor didn't stop, from what I understand you only have LOW speed now,,,correct?

 

Well when I first got the vette the wipers only went a constant LOW speed. Then I took the switch out, took it apart, looked at it put it back together and put it back in the car. After that I got the different speeds but still would not shut off. Than I took it out again cleaned it and greased it like you both said to do, and now I have LOW speed and OFF.

 

With the wiper switch in the LOW speed position and you check continuity from the single BLACK ground wire (150) on the wiper motor to the top (92) and bottom (91) wires of the 3 wire plug at wiper motor you should get continuity between them.
Wiper Switch OFF position you should only have continuity between 150 & 91.
If you get continuity between 150 - 91 - 92 in the OFF position that is why your wiper motor keeps running.

 

So cancel my last post,
Check continuity from 150 to 92 in HIGH speed position...

 

Your getting closer to figuring this out!!!

 

Using your photo, and tracing circuits from a 1980 diagram this is what I believe your wide connector at the wiper switch circuits are.
For reference use the OFF/LOW/HIGH circuit numbers in post #14.
A = is 7.5 amp feed from the instrument lamps fuse. It jumpers to the instrument panel printed circuit board.
B = Not Used
C = Circuit 92 Wiper Motor Switching
D = Circuit 91 Wiper Motor Switching
E = Circuit 150 Common Chassis Ground
F = Circuit 94 Washer Pump
So to be clear...Circuit 150 is the common SWITCHING ground,..NO POWER just grounds for switching
LOW speed Circuits 150 - 91 - 92 will be connected
HIGH speed Circuits 150 & 92 will be connected
Washer Pump Circuits 150 & 94 will be connected
I will let you connect the dots between switch circuits and actual switch Rails/Contacts...