I have a 71 coupe and can't seem to get the wiper moter working. All new wiring harness. I have read the Wilcox diagram and trouble shooting tips. I have constant 12v at the red/white wire at the wiper motor. The connector with the grn-yel-blu wires has the following--12v on the blu and green with nothing on the grn. I am thinkinking that 12v for blu and grn most be for hi-lo speed depending upon switch. I can not get the wiper motor to turn. The only way I did this was by sticking a screw driver on the blu wire on the connector (which i guess grounded it) while it was connected and the motor worked. I must not have a gnd somewhere. I need some help.

 

You have something wrong for sure. The blue and green wires at the motor should never have any current! These wires are ground wires. Something is feeding voltage to the blue wire.

Go to your relay and make sure the wires are on the relay in the correct position, make sure your wiper switch is grounded at the switch plate and make sure you have the ground wire on the wiper motor. You need to figure out the source of the 12 volts before you plug the motor back in.

Willcox Inc.

 

thanks, do you think i have a connector on upside down?? I am thinking wiper switch, that would put the blu wire on the wrong side. Or maybe the relay connector in the console. These are flat connectors that can go either way??

 

Are you doing this test with the 3 wire unplugged?

 

I measured the 12v's with it unplugged. With it plugged in I grounded the blu wire in connector with screw driver and it worked.

 

Unplug the 3 wire but keep the red single plugged in.This is direct from Wilcox test.

12 volts to the single red with white tracer
Ground to the wiper case.
12 volts to term. #2 (center one)(where yellow wire was connected)
Ground term. #1 and motor should run on high (where green wire "was connected)

 

If you have 12 volts on your green or blue with the 3 wire off you have a problem as Wilcox said.

 

Where can I get the diagram and trouble shooting tips?? My 70 only works on the bypass switch

MArty

 

http://willcoxcorvette.com/instructi...help_70-72.pdf

 

i did this test and the motor worked. So the motor is good. Red wire and gnd is also good. It has to be in the three wire connector on the blu side. i know i have a wiring problem. the blu wire shpould not have 12v. I believe I have a connector with the blu wire on backwards?/??

 

Lets back up a min.,did you use a voltmeter to measure the 12 volts at the #3 wire spade on the motor?If so I believe it will measure 12v because the motor is "trying " to go to ground through the very sensitive voltmeter--if you use a 12v test light and still get a bright light then you do have a problem in the motor.
If you are using a voltmeter I would like you to do a test of the lt green and wire through the wiper switch on the dash.
Pull the 3 wire connector off the wiper motor.
Set your meter to an ohms setting.
Move the wiper switch to high.
Ground the black probe of your ohm meter,now touch the lt green wire and see if your ohm meter goes to no resistance.Let us know.

If you are using a test light.
Attach the alligator clip to the pos connector on the alternator.
Now touch the probe end to any ground like the intake manifold and make sure the test light lights.
Pull the 3 wire from motor
Turn wiper switch to high
Now touch the probe to the lt green wire and see if it lights.
Let us know

I usually dont have to do all this testing but I think I have this procedure correct-If not someone will please chime in and correct me.
Where is Wilcox ???

 

I did use a voltmeter. I also tried to read the green wire with the voltmeter on ohms. It read low on the green wire at the 3 wire connector. When I moved the switch on dash to high no change. Actually all three wires read about the same with no change when moving the switch. I believe I need to look at that switch,,,,,,,,,,,this is getting to be a pain.

 

The switch might not have a ground.The switch must be grounded to provide a ground for the motor to run.If your center cluster is broken the top part that holds the wiper switch might be ungrounded.

 

ok, i guess i will check for gnd. Is it just grounded by the face plate. Or is there a gnd wire???

 

There are ground wires on the faceplate and the gage cluster is grounded by the center term. on the temp gauge.
If you want you can run a temporary ground wire to the switch.
(Caution-If the switch is not grounded and you turn it on and it grounds through you it will give you a good shock.)

 

-----Willcox


Roger and Kessler,

I'm back. . . I've been gone for a few days!

I'll read this top to bottom tomorrow when I get a chance.

I did notice one person saying that his system only works on the over ride. When this happens the tach solenoid is usually the problem.

When the over-ride (and yes Roger I get a pass on this one) vacuum switch operates the door and the electrical switch won't, more often than not there is a problem with the solenoid. The solenoid operates in a fashion where vacuum will pass thru it until the wiper switch is turned on. When the wiper switch is turned on the solenoid engages and blocks the vacuum. This makes the wiper arm switch (under the pass wiper arm) drop vacuum which in turn makes the wiper door actuator relay move to the up position allowing the door to come up.

We have found many cars with the solenoid either wired wrong, or bypassed due to failure. To do this customers will just bypass vacuum on the solenoid under the dash which creates a constant down position on the wiper door until you pull the over-ride which blocks it.

I hope this makes sense it’s late, I’m tired and I’ll have to re-read this tomorrow.

Willcox Inc.

 

If you have current on the blue wire and green wire you are back feeding voltage. This can be caused by a lack of ground as Dwncchs said.

On the back of the center dash bezel, there is a connector where the gauge cluster ground plugs in to. This connector grounds out the center gauge bezel and the wiper switch and is located on the lower section back side. It can be accessed by taking the passenger side lower dash pad out. When the cars age, the center dash bezel will break in the tiny area of the bezel and the switch will loose its ground.

Also check the connector at the wiper switch and make sure you have it in the proper position. If the switch connector is on upside down this will cause this problem. In what order are the wires at the switch from left to right?

Go to the relay and check verify the black and black with white stripe wires are good grounds. Make sure the ground from the motor can to the motor is good; this is the jumper wire that runs over to the blower motor ground.

To test for ground, simply find a 12 volt supply with your test light and touch it to the wire or area that should be a ground. In other words, if you want to see if the wiper ground is working, hook up your test light to a 12 volt supply and touch it to that wire. If it lights up, then you have a verified ground.

To make sure all wires are going to the correct place ping them with an ohms meter. With some extra length of wire you can test from the switch to the outside connection real easy. This will tell you for sure the wires are in the proper place and going where they should.

Try these things and then post again,

Willcox

 

thanks for the great info. I will try these things when I can get back in the garage. I am out of town for a few days.

 

Sorry for the long delay but i just got back to work on it. here is how the console wiper switch is connected--pass side blk, blk-wht, blu-driver side. the wiper motor connector is connected--pass side grn, ylw, blu-driver side. is this correct????.

 

The connector on the wiper switch can be plugged in backwards.
make sure your wiper switch is grounded.
also make sure your wiper motor is grounded.
all of these are common problems. 69VETT