Hi,

I just bought my first vette. It's a 71 NOM that needs a lot of work. I can't drive it since it will not pass safety inspection. The first of many things I'm trying to fix is the wiper. This is my first time working on a car and I'm not sure whether the problem is the switch, motor, or wiring.
I bought a test light to see whether there is power going into the motor. Below is what I found:
1. Ignition off
No power on all six wires shown in the pictures below.
2. Ignition on, wiper door open or closed, wiper switch off
Power on light blue, both yellow, and dark blue wires.
3. Ignition on, wiper door open or closed, wiper switch on
Power on both yellow and dark blue wires.
I also tried turning the wiper override and it didn't work either.
I think someone must have bypassed the wiper door switch that sends power to the motor. I see a connector coming out of the wiper door switch that is not connected thus the assumption.
Can someone explain to me what's the function of each wire? I'm guessing black wire is the ground but have no idea what the other five wires do. Any idea why my wiper is not working? What should I do next to determine whether the problem is switch, motor, or wiring. Thanks.

-Peter

 

The plug that is bypassed is the one that goes through the switch that carries power to the motor only when the door is open. If your wiper motor worked, if its bypassed the wipers might ram the wiper door if it failed to open. I'll dig out my wiring diagram and tell you about the other wires tomorrow if no one does before me.

 

Thanks. I'm just assuming the wiper door switch was bypassed since the plug was not connected. Maybe that is my problem.
My wiper door is not working either so I don't have to worry about the wiper door slamming on the wipers. I just need to get the wiper to work so I can get the car inspected. I'll probably be turned on once a year during the yearly safety inspection.

 

not sure if this will help but you may want to check
the overide switch under the steering colum

 

Yes, I did. It didn't work. Thanks.

 

Okay, here goes-
the red wire that goes to your bypassed wiper door switch is an "always hot" wire that should go to the wiper motor. The wire is separate and is to the left side of the wiper. It is the most common problem. If that hot wire is not connected, no wipers. I could not tell from your pics if that is connected. The first pic that you show is the washer, so don't worry about that until you get the wipers working. The second pic shows the black ground wire and the plug that goes to the control via a big multi-wire connector. It acts as a variable grounding control, with the voltage difference determining the wiper speed. The center wire of the plug should be on when the ignition is on. One of the outside terminals the plug plugs into is a ground. I don't remember if it is the green or blue, so unplug the plug and check continuity from each outs terminal to ground and that should tell you. The other outside terminal is the one that is switched to ground by your wiper controol. When the wiper is trurned on and everything is working right, a solenoid that the center terminal and the control terminal activate will start your wipers. This sounds confusing, but don't worry. It is. There are a lot of other things about parking the wipers, etc., but this should give you a start. If this is not clear, PM me and I will copy the diagram and send it to you. Good luck!

 

From my drawing, it seems that green is ground and the blue is switched.

 

Also in your last pic there is an L shaped arm coming through the firewall. This arm engages a micro switch when the wiper door is fully open. This switch then energizes the wiper motor......your switch looks to be engaged....was your wiper door open when the pic was taken? If the micro switch is engaged but the wiper door is closed the wipers would slam into the door and remain frozen. This could have over time burned out the motor.

 

Thanks. My wiper door was open when I took the pictures.

 

Thanks. I think the red wire that's always hot is my problem. I don't see any red wires going into the wiper. I saw a red wire that goes from the connector that supposedly connected to the wiper door switch to a "relay?" in the second picture. I checked the red wire as well as the connector, there was no power at all.

 

Attachment 47595544

The plug in your pic that has a red wire stuck into it should be hot on one side and the other should go to the wiper. I don't know if the wire stuck into it is always hot and going to the wiper or not. The pic above below shows where the red wire goes into the left side of the wiper motor. I'm going to PM the drawing I have.

 

I connected the plug from the limit switch and I got power from the red wire to the wiper motor. However, my wiper still doesn't work. I believe my wiper is bad. I removed the wiper motor and connected it directly to the battery, it did not turn. Am I correct assuming my motor is bad?

 

Put a new wiper motor in today. Now I have a working wiper ready for safety inspection tomorrow. Thanks to all that have replied.