Electrical help needed with wipers
Thread Starter
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
Electrical help needed with wipers
So before installing my dash I made sure my wipers were working. So I've now finished installing the dashpad, drivers lower pad, and gauge console but I find my wipers no longer work.
I know I have electricity to my wiper override switch:
as well as my wiper limit switch:
I'm thinking there's a ground problem. I don't believe that the wiper switch itself
needs to be grounded as it's plastic.
I'm pouring over my electrical schematics trying to figure out what to check next.
When the car is running, if I turn the wipers on, the wiper cover (it's a '71) pops up and should hit the limit switch. I've verified that the limit switch, when the cover is open, does have continuity on the in/out wires. When I switch on the wipers I do hear my wiper relay click:
With these little glitches, I'm really hating putting my interior dash together.
I know I have electricity to my wiper override switch:
as well as my wiper limit switch:
I'm thinking there's a ground problem. I don't believe that the wiper switch itself
needs to be grounded as it's plastic.
I'm pouring over my electrical schematics trying to figure out what to check next.
When the car is running, if I turn the wipers on, the wiper cover (it's a '71) pops up and should hit the limit switch. I've verified that the limit switch, when the cover is open, does have continuity on the in/out wires. When I switch on the wipers I do hear my wiper relay click:
With these little glitches, I'm really hating putting my interior dash together.
Instructor
Joined: Oct 2009
Posts: 178
Likes: 7
From: issum Germany
Turn the wire plug 180° on the wiper switch. It fits both ways. I had the same problem after reconnecting the wiper switch. May be it works. Does the washer pump work as it schould do ? If not this would be the answer.
Thread Starter
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
Roger,
I did notice that having a ground on the switch is important as when I was playing around with the cover plate, sometimes it would touch the gauge cluster metal and make ground, causing a clicking sound in my relay.
I've taken some time to edit a electrical schematic I have to only show wipers. This might help illustrate where my issues are. Note: the schematic doesn't show the wiper switch being grounded, but it does need to be.
I did notice that having a ground on the switch is important as when I was playing around with the cover plate, sometimes it would touch the gauge cluster metal and make ground, causing a clicking sound in my relay.
I've taken some time to edit a electrical schematic I have to only show wipers. This might help illustrate where my issues are. Note: the schematic doesn't show the wiper switch being grounded, but it does need to be.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
The wiper switch picks up the ground through the center dash bezel so when you bolt in the plate to the bezel it should be good to go. If the center dash bezel is broke at the thin section you should run a jumper wire from the wiper switch bolt to the back side of the center dash bezel. For testing though just remove the wiper switch plate and clip a ground on it.
You say the motor is just making a clicking noise when you try to operate it. Have you tried running an extra ground to the motor case? In most cases when you have a motor that only clicks it is a ground issue.. So jump an extra wire or check the existing one... then move on.
Have you looked at this page on the web site? The wire diagram there is in a higher quality and will show you which wire belongs on what terminal on the relay and other parts. http://willcoxcorvette.com/repairand...elp.php?hID=95
Last edited by Willcox Corvette; Jul 7, 2012 at 04:18 PM.
Thread Starter
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
Yes that ground is connected, verified several times. However your picture is a bit different than mine in that it looks like you have 2 black ground wires coming from that connection. Is yours a '71? I only have a single black wire coming off that connection.
The motor is a rebuilt unit that has about 30 rotations on it from previous testing, it should be good.
I did some testing of the relay to see when and where I had 12v. Here's a chart of the relay that goes over the transmission hump:
Code:
Voltage?
w switch off low high
--------------------------
Yellow | 12v | 12v | 12v
Lt Blue | 12v | 0v | 0v
Grounded ?
w switch off low high
------------------------
Lt Green | Yes | No | No
Black
Black
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Thread Starter
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
You say the motor is just making a clicking noise when you try to operate it. Have you tried running an extra ground to the motor case? In most cases when you have a motor that only clicks it is a ground issue.. So jump an extra wire or check the existing one... then move on.
Thread Starter
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
I've verified that my wiper switch is in correctly. I tested the switch and 1 and 2 will have continuity when the washer button is pushed. I did notice one odd piculiarity in that the washer ground (1 and 2) only seems to work on the Low setting.
Thread Starter
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
What I find odd to me is that with the wiper switch in the OFF position, the Light Blue wire at the wiper motor (part of the 3 wire harness) has 12v on it. I thought that wire was only used for ground?
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
That wire is looking for ground so the motor will work. The wiper motor already has power that is going through the motor windings and showing up in that wire. When it is grounded it completes the circuit for the motor.
Thread Starter
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
Out of desperation, I pulled my wiper motor out and tested it, it works just fine.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
edit- If your going to test the lt blue for power after you unplug the solenoid,unplug the yellow and blue at the relay also.
Last edited by ...Roger...; Jul 7, 2012 at 08:48 PM.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
When you don't have a motor ground the motor relay usually clicks 
Is the dash bezel broken at the thin area and if so did you run a jumper. If not, no worries.. just run a temp and see what happens.
Are you sure the ground to the speedometer is hooked up? It has to be something simple... The grounds are: Wiper switch, (to dash bezel center), Relay (though the dash ground) and wiper motor (through the blower motor)
When you turn the key on.. are the gauges working?
Is the dash bezel broken at the thin area and if so did you run a jumper. If not, no worries.. just run a temp and see what happens.
Are you sure the ground to the speedometer is hooked up? It has to be something simple... The grounds are: Wiper switch, (to dash bezel center), Relay (though the dash ground) and wiper motor (through the blower motor)
When you turn the key on.. are the gauges working?
Last edited by Willcox Corvette; Jul 7, 2012 at 10:03 PM.
Thread Starter
Burning Brakes
Joined: Feb 2011
Posts: 850
Likes: 12
From: Shakopee MN
doomkopf
I had my drivers dash out a couple days ago to work on other things, and figured that since my speedo night lights worked, surely I must have my grounds connected. Unfortunately I didn't know that the two ground wires going to the speedo and tach did different things, I incorrectly thought they were grounds for only the lights. WRONG WRONG WRONG.
Many thanks for jogging my brain on that one!!! Onto the next part of the dash assembly.
Humbly yours,
Jeff
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Good Deal.. Glad you found it. That speedo ground is what grounds the relay.. without it.. nothing works..
I'm also glad you didn't have to tear the dash back out...
Willcox
I'm also glad you didn't have to tear the dash back out...
Willcox