I was trying out systems on my new to me '69. Headlights, taillights all worked. I tried the Wiper switch and the Wiper door raised and the wipers started. I was a happy camper. Then I tried to turn off the wipers. They just kept going. I moved the switch to the left as far as it would go, but the wipers just kept going. I turned off the car and the wipers stopped but I don't think they went all the way to the park position. I could use the Wiper door override to open and shut the Wiper door. It seemed to contact the Wiper arms but I was able to give them a slight push and they moved enough so the Wiper door didn't contact them. The wipers did not start up again when I restarted the car.

Someone has been fooling with the Wiper motor. The plastic cover is missing and someone rigged up a ground wire from the case to a bolt on the intake manifold. There is only one rubber hose connected to the washer pumps (I have one on either side of the pump housing).

The Wiper override switch didn't seem to have any effect when I had the Wiper door opened.

Any suggestions appreciated. Hopefully something simple and quick to repair!

 

To the best of my knowledge the 69 wiper motor is a 1 year only and very expensive. The **** between the 2 vacuum override switches is to allow you to stop the wiper travel so you can change the blades. From 69 to ? there are headlight washers which is the reason for the other hoses. From your description my suggestion would be to make sure the wires are hooked up to the motor correctly. We have a forum member that supplies us with a schematic and if you can't find him lets us know and we will find him for you. Another source is Wilcox corvette, a forum vendor, they have an extensive tech help library with lots of wiper info. T

 

Thanks.

I read the owners manual and realized that the Wiper override only stops moving wipers. I thought it manually turned them on, so I wasn't trying it when the wipers were moving.

So I assuming the actual Wiper switch is bad if it won't de-energize the Wiper motor...

 

theres a specific cicuit built into the wiper motor for parking them. One of 2 things obviously possible.
1. your switch is bad and wont denergize the wiper motor
2. the parking system built into the motor failed

(Less obvious would be something else in your system I'm not familiar with. I have a68 and its its own creature.)

I had both happen to me. The wiper switch was melted by the previous owner, I bought a new one and it failed after 3 uses while alignining the arms so I had to buy a used one from George. I also had to buy a new motor and it came improperly assembled. Theres a c clip that holds the axle and the bushings and mechanism together and it wasnt installed properly so the motor wouldnt park.

First thing I would do is go to the Willcox site and look for the bench test for your year motor. You can perform it with the motor installed. that will tell you if its good.

 

The wipers have TWO sources of power-

1)The yellow wire switched from the ignition-

it controls/energies the solenoid that switches to park.

2)The constant hot power wire- red and white.

It supplies the actual wiper motor, power.

That power goes through the service/ wiper over-ride switch then to the open/limit switch on the firewall- the one that makes sure the wiper door is completely open before the wiper motor is powered.

The switch in the dash JUST controls the grounds- as its done by a combination for park and hi/low speeds by the green and blue wires

Park= green is grounded
Low speed=Green and Blue grounded
High speed= blue is grounded


BTW- it's the 68's that are a totally different animal....

 

The first thing you should do is upload a copy of this.... it's free.

1969-1972 Corvette Windshield Wiper Motor Tech Help, Wire Schematic With Test

Then I'd suggest is to remove the bell crank from the motor, remove all wires from the motor including the ground. Run test leads from the alternator or another 12 volt power source and grounds as shown in the video below. Do this and make sure the motor is working properly, then dig in.

Wiper Motor Bench Test 69-72



Willcox Testing a 68-76 Corvette Wiper Motor Switch


Willcox Testing a 68-72 Wiper Relay


Then there are these links that should help you diagnosis the issue.

1969-1972 Corvette Windshield Wiper Motor Tech Help, Wire Schematic With Test

1969-1972 Corvette Wiper Motor (How to rebuild it) From the original GM Service Manual

And lastly... here is all the information I have on my tech page in regards to a 1972 wiper motor.

http://repairs.willcoxcorvette.com/?yt=1972&s=wiper

Richard. I updated that picture to include the fuse in the fuse panel



1969-1972 wiper motors are all the same.. The washer pump/headlamp pump is what is odd about the 1969 system which used an extra pump and solenoid for the headlamp washers versus the system used later in the pump. Then you have 1970-1971 with five ports then 72-74 with three ports.

Willcox

 

Thanks! I'll have to figure out how to get the motor and pump out of there. Not much space with the ignition shielding. Then break out the multimeter.

 

Does the fact that my motor runs and the Wiper door functions help narrow the testing? Seems like the motor testing shown is to figure out why the motor doesn't work. I only saw one situation where the motor continued to run but when that was happening, the motor was making a clicking sound that mine did not make.

 

Use a continuity tester-

Disconnect the plug at the wiper-

See if the green wire at the motor is seeing a ground - when the wiper switch is off

Take the meter - and see if there is power at the yellow wire when you turn the ignition on. (switch still off)

I'm thinking it a bad solenoid on the back of your tach -

Let us know-

 

you dont have to remove the motor, you can do all the tests with it installed. testing it will remove the possibility that it failed. then start testing the other parts in the system