Testing Wiper Switch '76

Reply Subscribe

Thread Tools

Search this Thread

Jun 16, 2018 | 11:22 AM

DR76

Thread Starter

Pro

Joined: Jun 2001

Posts: 708

Likes: 0

From: Florida

Testing Wiper Switch '76

'76 - Not getting wipers to budge. I located a very handy .pdf file on motor testing on Willcox Corvette's site and looks like motor is fine. as it does everything it should (High, Low and Park) when applying grounds and power to the pins as directed to do.

Does this necessarily mean that the switch is bad or can there still be a grounding issue to the switch???

This is what I performed, as per the Willcox instructions:
(*Note: I also have a ground not mentioned in the Willcox steps, which I labeled 4G in the pic. 4G is definitely a good ground)

Supplied 12V to pin 2M, Grounded 1M = High Speed
Same as above, but added ground to 3M = Low Speed
Removed ground at 1M (3M still grounded) = Park Position

All worked fine w/o issue.

Using a Power Probe tester I am getting 12V to the harness side at 2F in all switch positions (off, low, high) , but Power Probe isn't detecting that 1F or 3F are ground signals in any of the switches positions.

I believe I read somewhere (maybe on Willcox's site???) that the center cluster comes into play w/ grounding to the switch... how would I test this?

Thanks for any input

Last edited by DR76; Jun 16, 2018 at 01:07 PM. Reason: ...

Jun 16, 2018 | 12:13 PM

DUB

Race Director

Joined: Apr 2009

Posts: 19,294

Likes: 2,753

From: Charlotte NC

Unless you wrote it incorrectly.

Unless something has changed I was ALWAYS under the impression that at least 1M or 3M has to have a ground on it to go into PARK.

I know that if grounds are on 1M and 3M that is low speed.

IF you are not getting grounds switching on 1F and 3F...then I would have to look at the wiper switch. Simple as that.

DUB

Jun 16, 2018 | 01:05 PM

DR76

Thread Starter

Pro

Joined: Jun 2001

Posts: 708

Likes: 0

From: Florida

DUB... yes, "3M" still needs to be grounded for PARK (the wipers must have been close to PARK when I removed both grounds and I mistook that it was there) Thanks - post updated

Was still kind of curious about the grounding thru the center gauge cluster... anyone ever hear of this? Probably just pick up the switch anyway ($30), but if it doesn't fix it, I have another path to look down...

Jun 16, 2018 | 06:45 PM

DUB

Race Director

Joined: Apr 2009

Posts: 19,294

Likes: 2,753

From: Charlotte NC

Yes...the wiper switch that is bolted to the gauge cluster needs to be grounded and I would bet that it is.

But before you go out and buy a new switch I would get to it can check it out. You could possibly have a wire that came out of the connector.

DUB

Jun 18, 2018 | 04:08 PM

0Willcox Corvette

Former Vendor

Joined: Aug 2006

Posts: 76,656

Likes: 1,850

From: Jeffersonville Indiana 812-288-7103

St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15

If the center dash bezel is broken at the thin area below the wiper switch mounting plate then odds are you'll need to run a jumper from the switch to one of the gauge cluster screws. The wiper switch must be grounded for the wipers to work properly.

If this isn't the issue, then here is how to test the actual wiper switch.

Willcox Testing a 68-76 Corvette Wiper Motor Switch