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Topic: My wipers don't work

in Forum: C3 Electrical

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My wipers don't work (1/10)
10/11/15 5:03am

Grahamred70
Former Member
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 83

Finished the brakes, got all the lights sorted, fixed the horn and now I find the wipers aren't working!

If I pull the knob under the dash the door opens, if I operate the wiper switch with the door closed or open nothing happens.

I looked at the Willcox help but that only covered post '73 wipers and mines a '70, one thing I did find was the relay which holds the door open until the wipers have parked seems to have exploded but that shouldn't affect the wiper operation as that's not electrical.

My motor has the 3 main connections arranged vertically and another single connection with 2 wires on it to one side, I've got a power probe so which terminals need live and which need earth to test the motor?

Which way does the knob under the dash need to be to power the wipers, clockwise or anti clockwise?

Thanks

Graham

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Re: My wipers don't work (2/10)
10/11/15 12:08pm

Adams' Apple

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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 20128

Graham, I'm sending you (email) a complete guide for troubleshooting the wiper/headlight vacuum and electrical stuff. Hope it helps you out. Wink

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Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

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Re: My wipers don't work (3/10)
10/11/15 1:53pm

Grahamred70
Former Member
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 83

Thanks a lot for that Joel, I've been trying to test the motor in situ today but not had much success, with the outer 2 terminals to ground and power to the centre terminal all I get is a click from a relay, which seems to be under the motor cover, but no movement from the motor.

The red/white wire which passes through the limit switch appears to be earthed when the door is open.

The three wires in the connector with the switch off and ignition on are green earth, yellow live, blue live.

In the low speed position the yellow remains live and green and blue seem to be a poor earth.

In high speed yellow remains live green goes to open circuit and blue seems to be a poor earth.

With everything connected up normally there is a click from the relay when switched to slow, I guess this relay opens the vacuum to open the door? but on mine this doesn't happen, when I press in the washer there is another relay operating but no reaction from the pump.

That's as far as I've got so far, I'll study your excellent info tonight and then maybe I'll see something amiss.

Thanks againGraham

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Re: My wipers don't work (4/10)
10/11/15 2:18pm

eldredjames

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Temple City, CA - USA

Vette(s):
1969 Daytona Yellow. 350 / Automatic.

Joined: 10/3/2010
Posts: 365

Try this guy http://www.docrebuild.com/dr-r-web/aaa-home.html

I bought his guide and new vacuum hoses to get my wipers going. Also needed a new motor off of ebay. Most of our sponsor sites have wiper guides too.

Be careful. There are some plastic pieces in there that break easy. I'm still looking for a new headlight pump but don't want to shell out the $165 or so they want on eBay. All that I broke was a small plastic piece that sends the water pulses to each headlight.

Jim

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Re: My wipers don't work (5/10)
10/11/15 2:46pm

F4Gary

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Grapevine, TX - USA

Vette(s):
1972 LT-1 convertible with factory air.

Joined: 8/26/2006
Posts: 1409

Make sure the plunger on the firewall is fully depressing the button when the door is open.

You blokes talk funny. Beer

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Re: My wipers don't work (6/10)
10/13/15 11:42am

Grahamred70
Former Member
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 83

Managed to get the wipers working last night, not really sure what I did but the main issue was no supply to the red/white wire to the motor, I had 12v at the horn relay but not at the motor, I think it could be a bad connection as after pulling down the wires at the isolator switch under the steering wheel the system came alive.

I'd taken the wiper door off for access so while I was in there I set the blade positions to stow correctly without crashing into each other on their way across the screen and without going over the screen edge.

Proved the wipers work only with the door open, will see if they work properly with vacuum tonight and see if the washers work as well, hope they do as that needs to work for our MOT (road worthiness test) which it needs to pass before I can get her registered.

Many Thanks to everyone for your assistance and pointers to information.

Graham

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Re: My wipers don't work (7/10)
10/14/15 5:08am

Grahamred70
Former Member
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 83

OK wipers still work, door doesn't open when I switch them on but as soon as I open the door with the by pass button under the dash they work fine so that's good enough for now, don't relish pulling the dash down to get to the vacuum solenoid behind the tacho until I have to go in there.

Couldn't get the washers to function though, tried fitting a priming line with a funnel to put a head on the suction but all I got was water dribbling out of the headlight washers.

Unless there's a quick fix for the pump I'll fit an electric pump near the bottle and plumb it into the bottle, if I do that I need to know where the switched earth is that is connected to the pump on the wiper motor?

So far I've found the 3 wires that control the motor, the casing earth, then there's a blue and a yellow I think which go into the plastic cover over the gearbox but I believe they are to park the wipers?

Wire colours are a bit of a problem as a PO has sprayed everything under the bonnet with black paint :-(

How do I remove the plastic cover over the gearbox to get access to the pump drive, don't want to pull at the 2 wires there in case I break something.

Many Thanks

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Re: My wipers don't work (8/10)
10/14/15 4:51pm

Grahamred70
Former Member
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 83

Right, took the bull by the horns at least the 2 wires on the plastic casing anyway and they're actually the ones that control the washer pump so now I have washers as well as wipers, at least I will have once I've done a bit of plumbing so now I'm good to go for a shot at a test. I've seen repair kits for the pump are these still available? Regards Graham

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Re: My wipers don't work (9/10)
10/14/15 9:57pm

Adams' Apple

There are washer rebuild kits available. Some years have to use a later/earlier model kit tho...can't remember off-hand. Check with our Sponsor here...I think any of them will have the kits.

______________

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Re: My wipers don't work (10/10)
10/15/15 1:18pm

Grahamred70
Former Member
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 83

Thanks Joel, for now I've gone with an electric pump I had in my "spares" box so now have working washers but will look into rebuilding my original pump over the winter.

Mine has the headlight washers so one suction and 4 outlets.

Many Thanks

Graham

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