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I am fixing my wipers on my C3 1972 and although making some progress, I am now stuck and could use some advice.
I have replaced the wiper motor and have confirmed it is working. However, I noticed I did never get any ground on the
blue wire leading in to the motor, which apparently is what starts it off.
After checking all my grounds and properly grounding the control switch I now get ground when pushing the switch for Washer.
The motor also kicks of for a couple of revolutions. However, it does nothing when moving the switch to speed 1 or 2. Only when I
press it in. I have tested the switch with a test light and it appears to work as expected. I am now starting to think it might be the relay,
but would the motor even work when pushing for Washer if the relay was dodgy? Anyone come across the same issue and if so, what
was the cause? Thanks for any input.
I can only tell you what I found while working on my 78 which is different than yours. The washer pump is triggered by the switch sending it a ground signal. It does not send it power as it does for the wiper motor itself. Yours might be different. I would put power each wire coming to the wiper motor with out the switch and see what happens. I would suspect the switch if it works only while pushing it in.
Yes I have watched numerous YouTube videos now on how the motor works. Like you said, the motor always have power and the control switch sending it ground to different
inputs to start it, change the speed etc. I have tested the motor outside the car and can confirm all the functions are working as they should, which I would
expect as it is brand new. I was also suspecting the switch, but I have checked the different positions with a test light, and they all seem to work.
Also, the motor - switch connection must be working, as it starts when I press the lever in for the washer.
On the switch you'll notice a tang. This tang is to help prevent the connector from going on backwards but the connector can be put on backwards. You have the classic connector on backwards symptoms. See if it's that simple. I hope so.
I edited and updated this GM document for the wiper circuit. It was for a 69, but the basic function did not change for several years.
Hopefully it might help you.
Thanks Robertea,
This is really good. It is the light blue wire that is not sending ground to the motor.
It seems to go straight to the motor, so that means that it must be something with either the cable or the switch.
I will try to first ground it manually and see if the motor starts, if that does not work I will check that the cable is
in fact not broken somewhere with my multimeter. If not broken, I know by elimination it must be the switch.
Thanks heaps for this.
Hi Robertea,
I am missing one cable in your diagram. It is the dark blue from the switch.
It is in the table in the upper right corner, but not in the diagram?
Where does this go?
The dark blue wire goes directly from the switch to the bulkhead connector (it is the 18 DBL wire in the image) and then goes to the washer pump on the wiper motor.
When you press the wiper switch in it supplies a ground to the washer pump and the wiper motor is turned on by the other connections in the switch.
This is a bit embarrassing, but you were correct. I had the connector upside down.
Mind you, the switch also did not work, so I had to take it apart and fix it.
The connector was already on the wrong way when I took it apart so someone else must
have worked on it. I also thought the whole
reason for the tang was to line it up with the one on the connector.
Wiper control switch troubleshooting
