Ok, Got a rebuilt wiper motor and the first one did a bench test and was DOA. The second one I just got in and did the bench test and seems to work.

I plug this all in the car and nuttin. I have new EVERYTHING, harness, relay, wiper cut out switch, interior bypass switch, dash switch...

I have 12v to the yellow, I have 12v to the red when the door is open. By pass switch is not in bypass mode. I turn on the accessory power and trun on the wiper switch and nuttin. What am I missing? Does it need to be running? Does it have something to do with the relay behind the tech that needs vac?

This car is not ready to be started (has never been started since I had it). Let me know if I am just not understanding...

 

Where's your ground?

 

the motor housing needs a ground!

 

Well, the harness has a ground wire that works for the wiper motor. That is plugged into the ground connector on the motor. I tested all 12v lines against the ground and completed the connection. Is there another I could be missing?

 

Ok just tested.. More info... The ground is good... BUT from looking at some videos online I understood the connector that holds the Green, Yellow, Blue... The Yellow was to be a solid 12v and the Green and Blue were grounds for the Hi and Low speed... When I test the 3 prong I get 12v on the green not the yellow?! When I bench tested the motor I hooked my 12v lead to the center term where the 12v was to be and the motor works!

So, I know that this all runs to the switch and the relay under the radio. My only questions are...

1: On the wiper switch on the dash what way does it plug in (colors) from right to left. Not sure if I have this switched up (no pun intended).

2: On the wiper relay there are two plus to it. The one can only be plugged in one way, the other is a yellow and blue that is vertical. What color is on the top and the bottom.

Not sure what else it could be. The over ride switch is passing power as I checked that as well. Is is possible that it is a harness issue where the yellow and green were swapped at the connector under the radio? Anyone have picts?

 

Would anyone be willing to pull off the 3 prong connector to the wiper motor? Then turn on Acc power and take a multi meter from the ground to the Green, Yellow and Blue. I am guessing that your yellow has the 12v where my green does. Can anyone confirm? I just looked at the wiring diagram and everything is plugged into the switches, relays, etc just as they should. The only thing that does not seem to match is this 12v on my green wire at the wiper motor.

 

As does the switch.

 

This being the off switch in the dash? That has a ground line form the switch case to the body ground?

 

The switch in the center bezel gets grounded through the switch housing via the gauge bezel. If the gauge bezel is broken there will be no ground to the wiper switch. To clarify, the wiper motor has a ground connection separate from the 3 wire connector. If there is 12 volts to the yellow wire and ground to the motor case, then ground the terminal where the green wire hooks to the motor, it should run.

 

Hum, will be sure to check this as I have digital gauges form Dakota Digital. So, I do not pull a ground to this area and the lighter ground was not hooked up. Will give that a try. Thanks.

 

When you turn on the motor do you hear anything?

The reason I ask and a new item of importance in 1969-1972 testing is this:

If you hear the relay click in the console, the wiper switch is grounded. If the wiper switch is not grounded the relay will not click!

Boy.. I have a new video in the works for this but just don't have it finished.. It will be similar to the one we did with the 68 motor called putzing around. I just don't have it completed. But in this video we removed each wire from the system one at a time. (you guys should love this video)

Let me review my notes and post back.

In the meantime have you reviewed the page below? And if you go to the same page for the 1968 cars you'll find the readings for the wires on the last page.

Corvette Windshield Wiper Motor Wire Schematic 69-72 with test

 

I may be able to finish this video this weekend..

But.. if you have no clicking at the relay my guess is wiper switch not grounded. A simple way to find out is to just run a test jumper wire to the wiper switch ground plate.

Now.. as promised above.. here are my notes from the last video on the wiper motor and as soon as I can I'll try to have this one up.

WARNING.. the notes below are a copy and paste and have not been edited... expect typo's.. To make any sense form this madness.. use the schematic I posted above.

Blue wire at motor connector disconnected number 3 in our schematic
(top wire on the 123 connector)
You’ll get nothing on either speed but you will hear the relay click.
This blue wire runs to the wiper switch, the tach solenoid, the relay and to the motor. In our schematic it touches terminal numbers 3-16-18-11

If you hear he relay click, the wiper switch is grounded.

Green wire bottom wire disconnected or number 1 in our schematic on the 123 connector.
If the green wire broken you will have high speed only on motor and when you switch back to off (or park) you get wiper motor run on. (Don’t let this run long like this, it overheats the resistor).

Yellow wire broken at motor or 2 in our schematic. You will get nothing! No power. You will hear the relay click on both speeds.

The dark blue wire number 17 in our schematic at the switch. This wire is just the ground for the washer pump it will not play any roll in your wiper motor working or not working.

Wires at relay.

Blue wire runs from relay to wiper switch and is the ground on the wiper solenoid. Drops ground off relay. All you will have is low speed and the motor will park. You will not have high because the relay will not ground and switch.

Yellow wire kills motor

Green wire.. Same results as pulling it off at the motor. You'll have high speed only and wiper motor run on.

The black with white stripe wire number 8 on our schematic or the middle wire on wiper switch. This wire runs from switch to the relay. With it broken you will have high speed only and you will park.... you will not have a low speed.. and the relay still switches.

Ground missing from the switch.. you get nothing..
No click at the relay, nothing.. entire system will be dead.

Key on:
Green = no voltage
Yellow = 12 volts
Blue = 12 volts

Key on Wiper switch on high
Green = 10.30 volts
Yellow = 12 volts
Blue = 160 millavolts

Key On, Wiper switch on low
Green = 1.4 volts
Yellow = 12 volts
Blue = .3 volts.

 

That is some awesome info! I know for a fact that the switch is not grounded in the console. I replaced my gauges with all digital and the ECM is grounded not the console. So, I will hook up the ground and test further. I guess the only think I dont understand is this...

Key on:
Green = no voltage
Yellow = 12 volts
Blue = 12 volts

When my key is on I have 12v at the green!? Nuttin on the yellow or blue (well maybe some like 0.2) If the green is having the 12v could this be due to having no ground on the switch?

 

With the key on and 12 v on the yellow, the motor will be "seeking" ground through the green and or blue unless one or both are grounded from the switch. You are reading the voltage coming through the motor windings. Its possible your dash lights or gauges are seeking ground through the wiper switch also.

 

Ok well got that center console grounded... Almost embarrassed to say... it works! Thanks for the help. I just never would have thought that switch would need it's own ground.

 

The switch is a series of grounds.. and with no path to ground.. we'll it can't do the job. The wiper system(s) is basically a "Hot all the Time" circuit.. waiting for ground!

Merry Christmas, glad you got it fixed.

Willcox

 

Merry Christmas to you as well. Thanks so much for all the help.