72and86

The vacuum system works great on my 1969 base motor Coupe including the wiper door but after the wiper door opens, no response from the wiper motor. No wipers response.
what Ive done:
• Fuse checks out
• Wiper door opens
• Good ground on wiper switch
• Wiper Switch contacts checked and cleaned
My mechanic friend says cause of the motor orientation its hard to test directly…ugh

The switch feels good, but I’m not sure how to bench check it. I bought a new switch and it feels like garbage. I did NOT install it. The switch barely moves. This si the second switch Ive bought for C3s that is inferior in quality.

How do I check the switch or what else have I missed? Everything works on this vette but the damn wipers!
Thanks guys!
Steve

Alan 71

Hi Steve,
Is the plunger on the wiper door safety switch pushing the button on the switch which completes the circuit to the wiper motor?
Regards,
Alan

72and86

Alan,
I will double check that but Im pretty sure the plunger works. How does this part of the wiper system work?
Are these switches prone to fail?
Thanks Steve

CharlyShino

Hi Steve,

I had the same problem. In my case a cable connection was lost at the wiper door solenoid.
In my mind there are two blue and two yellow cable connections in the solenoid and one of these blue was disconnected. Cause of this the wiper didnt work.

However, check out if there is power on the wiper motor. the red wire is coming from the wiper door limit switch and is only on power if the door is open. and another wire is continuously on power. if both work, there is ground problem.

Greets Michael

0Willcox Corvette

Here is everything I have for you on the 1969 wiper system.

First you should upload this file:
1969-1972 Corvette Windshield Wiper Motor Tech Help, Wire Schematic With Test

The wiper relay is located here on the 1969 cars.


Here is how you test it:


Wiper relay testing video


Wiper switch testing.


Wiper motor wiring diagram made simple


Wiper Motor testing with some Relay help


Wiper Motor Bench Test 69-72

TheFixer

Well, since no one mentioned the obvious, did you check the interrupt switch under the steering column? I must of bumped mine, since I had the same issue and scratched the head a bit till I checked it.

72and86

The switch that turns?

Also where is mentioned wiper relay? I see one on the PS by where the AC goes in the firewall....is that the AC relay?

Duh Ok I see he willcox posting. Really its under the shifter plate???

TheFixer

Yes the switch that turns. I don't recall which way to turn it tho. Mine used to click, but does not anymore. Not sure why, but still works. Probably why I ended up bumping it and turning them off.


You can check the relay by checking the voltages at the wiper motor when the switch is in different positions. Easier than pulling the center console.


Make sure you have the 12V first. I think the wiper limit switch in the Wilcox diagram is the pushbutton switch on the firewall that is pressed when the door is open. You need 12V out of that, or the motor won't run.

72and86

THANKS so much, TheFixer!!! That was it!! I figured I'd try the easiest fix. I turned on the console wiper switch after I hooked it all back up. The wiper door opened but no wipers and then turned the under dash dial switch and voila! It worked!!! Thanks so much to everyone!!
Ive only had the Vette since April so the PO must have played with it as he also thought the wipers didn't work.

What is the theory of having a second switch???

TheFixer

The wiper interior switch is so you can stop the wipers to change the blades. I bought in April too so you are a few weeks behind me on repairs.

Buy blades from a vette store. The autoparts store ones are too tall.

You probably need to bypass the headlight antI drip valve since they are 200 and don't ever seem to work.

72and86

Ahh makes sense. I noticed the under dash switch didn't CANCEl/PARk the wipers. Thanks

Rescue Rogers

Take a white paint pen and put a dot on the front of it. If you bump it you will be able to visually check it. I had that exact same issue and that was my solution

72and86

Where is THAT located?

TheFixer

It is mounted to the washer pump on the driver side of the pump. The 2 small hoses should come out of the pump into a Y then to a larger hose to the anti drip. From there one goes to the front, one to the headlights.

TheFixer

Anti Drip

72and86

Thanks, good to know. Something new I learned. However I will pass on this part of the system repair (if it's even broken). I hardly drive the car at night, much less through snow and slush to clean the headlamps. Maybe someday I'll get it to work just to see it squirt...

Too many other things need attention.
Just like; isn't there some kind of flow through vent on the back deck somehow connected to the vacuum system?

Alan 71

Hi Steve,
IF your car DOESN'T have air conditioning the Astro Ventilation system was designed to draw fresh air in through the cowl, have it enter the interior through the round vents in the lower corners of the dash pads and kick panel vents, and then exit the interior through vacuum controlled vents under the rear deck grills.
This system (open/closed) is controlled by the right side wheel on the heater/defroster control. It was designed to take the place of vent windows that were typical of cars of this era.
IF the car was equipped with a/c the system was inactive and the plenums to the rear deck vents were blocked off with a metal plate.
Regards,
Alan

Bremquest

Is this a 69? If so what motor is in it? Thank you