72 wiper motor not working.

[69CVET]

Ok Gents.
Seeing as the Vettes I have had all the wipers don't work need to get an overview on what should happen.

Current status.
1. Wiper Door Operates Ok both from the Switch and also Vac override switch below steering column

2. When 3 position selector switch is placed into Low or high speed Door stays open but no wipers.

3. There has been some wiring mods around this motor which from what I can see is a 71 wiper Motor on this 72 Car ....
Looks like 2 supply's to this motor ( can someone confirm this ??)

4. Also the main vac switch on passenger side below the wiper door only has 2 vac lines connected the 3rd has been cut just past the fire wall ?
Is this normal ???  - would think not.

Be great too see some photos if anyone has a chance to take a few to see what is the norm in this area.

Cheers Chris.

[Vettech]

I would have thought there would be two (2) supplies, one via ignition sw allows motor to return after wiper switch is turned off. The 2nd would be the supply from the wiper switch. Sorry I cant offer more as mine is a 78.(no door/relays etc) and the switch may be different.

[wabco40]

Ok Gents.
Seeing as the Vettes I have had all the wipers don't work need to get an overview on what should happen.

Current status.
1. Wiper Door Operates Ok both from the Switch and also Vac override switch below steering column

2. When 3 position selector switch is placed into Low or high speed Door stays open but no wipers.

3. There has been some wiring mods around this motor which from what I can see is a 71 wiper Motor on this 72 Car ....
Looks like 2 supply's to this motor ( can someone confirm this ??)

4. Also the main vac switch on passenger side below the wiper door only has 2 vac lines connected the 3rd has been cut just past the fire wall ?
Is this normal ???  - would think not.

Be great too see some photos if anyone has a chance to take a few to see what is the norm in this area.

Cheers Chris.

Hi Chris,

The open hose from the vacuum switch is normal as it is just a vent.

If the wiper door is opening and closing when using the wiper switch then the vacuum system seems to be in order.

Sounds like it could be the electrical limit switch on the firewall. When the wiper door is fully open a plunger pushes the switch in and completes the power circuit back to the wiper motor.
This needs to be adjusted so the switch is not activated until the door is fully open.

The picture shows the limit switch and the adjustable plunger between the wiper motor and vacuum actuator.

[Vettech]

That's a lovely blue. Does it look a bit purplish in the right light.

[N/A]

Some reference material.

http://repairs.willcoxcorvette.com/wp-content/uploads/2009/03/1969-1972-corvette-windshield-wiper-motor-wire-schematic-69-72-with-test.pdf

http://repairs.willcoxcorvette.com/wp-content/uploads/2015/04/1968-corvette-wiper-motor-updated-schematic-1968-1968-rev.jpg

I chased my tail a bit on my 69 wipers. Turned out to be a fuse ha.

[wabco40]

That's a lovely blue. Does it look a bit purplish in the right light.

Not that I have ever seen. It just goes different shades of metallic blue.

[69CVET]

Hi Chris,

The open hose from the vacuum switch is normal as it is just a vent.

If the wiper door is opening and closing when using the wiper switch then the vacuum system seems to be in order.

Sounds like it could be the electrical limit switch on the firewall. When the wiper door is fully open a plunger pushes the switch in and completes the power circuit back to the wiper motor.
This needs to be adjusted so the switch is not activated until the door is fully open.

The picture shows the limit switch and the adjustable plunger between the wiper motor and vacuum actuator.

Thanks guys good info will be helpful..

Cheers

[sirfixalot]

The wiper motor has constant  +supply on   red /white wire  supply comes via the switch under dash then the limit switch on firewall then to motor external wire & plug is a series circuit.The centre terminal on the 3 terminal plug is an accessory +. If the motor accessory + is turned off before the wiper motor parks it will stop & will loose the momentum which will open circuit the internal park contact inside wiper which then fails motor & won't restart. The motor has to be hot wired to restart it to then repark it.If you have a + on the external redwire & the centre terminal if you place a negative on the top  or bottom  terminal motor should run