Wiper Door Vacuum Control Solenoid
 

G'day Guys,
Just finishing putting the dash back together and am about to put the
wiring plug back on the wiper door control solenoid, but stopped to ask if the plug has to be a particular way round.

Mark

If it can assemble either way it should not make a difference. Is it the original unit, or do you have a new one? Have you tested it to make sure that it is working (whether old or new)? Now is the time to do that. When you get the dash put back together, you don't want to find out you have a 'dud'.

G'day 7T1vette,
Thanks for your reply, I thought that that was probably the case, only
2 wires and I know it works ok.

Mark

It will work flawlessly plugged in either way.

Thanks Willcox for the confirmation.

Mark

Oddly.. the solenoid doesn't have the little fingers on it to prevent it from being plugged in the wrong way... I just looked at a picture of a used one we posted up on fleabay. But I've tested these things over and over and inside is an electromagnet.. it will work positive or negative without issue.

What exactly does this thing do?

Hi bb,
The wiper solenoid controls the vacuum signal to the wiper relay valve.
When the dash wiper switch is off the solenoid is not energized; blue port maintains vacuum.
When the dash wiper switch is on the solenoid is energized; yellow port maintains vacuum.
Regards,
Alan

I'm not sure what you mean by maintains. I assumed it was vacuum in all the time and vacuum out when energized. My confusion is when the wipers are turned on, obviously the wipers go but there must be some delay from this switch to activate the door which might cause contact. If I had more time, I can't find any for sale on e-bay, I would sit down and look over everything but guys like you can point us in the right direction with such little vital information. Thanks Alan.

Rob

For the wiper door to stay closed.. you must have vacuum on the relay. On the 1969-1972 cars the hose from the solenoid runs to the over-ride under the dash, then to the wiper arm valve and then to the relay that operates the door vacuum.

Any of the three items.. the solenoid, arm relay or the over-ride have the ability to block the vacuum to the relay and when this happens the plunger in the relay falls and switches vacuum to the upward position on the actuator..

When you turn on your wipers they are ready to run.. all they are waiting for is the limit switch to be pushed on the dash... This is done when the door opens and pushes the plunger inward.

So in a nut shell.. the solenoid pass's vacuum.. until you energize it, which is also controlled by the wiper switch. The delay.. it is the limit switch being pushed.. (only happens when the door is open)

Confuse you yet.. :D

Interesting, unless someone just purchased it, I have the solenoid I used in our video for sale in ebay right now.. it's not new, but it is a perfectly functioning solenoid.

Here.. these pictures may help you.
http://willcoxcorvette.com/images/70...m%20vacuum.JPG

http://willcoxcorvette.com/images/wi...ic%2069-72.jpg

Great discussion, have a few questions myself
 

Great thread on this issue. I recently put my dash back together and the wiper door would not come up/ wipers would not work after i got it back together. It was working prior to the work.
When I pull the vacuum override switch at the bottom, I can get the wiper door to work. But the wiper blades aren't able to come on when I toggle the switch on the cluster.
Could the solenoid or switch be bad here? After reading the explanations, I wonder if having a bad solenoid could cause the problem, but I can get the wiper door to open with the override. Hard to trouble shoot.

pav
do you mean that the wiper door will not open if you toggle the wiper switch, or do you mean that the door opens and the wiper motor will not run?
if the door doesn't open, you may have crossed the two vacuum hoses on the solenoid. the solenoid vents the vacuum relay (causes loss of vacuum pressure) on the control line when the wiper switch is toggled. if the wiper motor doesn't run, you may have reversed the switch wiring plug(very difficult to do unless you really force it).

pav
do you mean that the wiper door will not open if you toggle the wiper switch, or do you mean that the door opens and the wiper motor will not run?
if the door doesn't open, you may have crossed the two vacuum hoses on the solenoid. the solenoid vents the vacuum relay (causes loss of vacuum pressure) on the control line when the wiper switch is toggled. if the wiper motor doesn't run, you may have reversed the switch wiring plug(very difficult to do unless you really force it).

The wiper door does not open when I toggle the wiper switch. The wiper door opens when I pull the vacuum override under the steering column though. I will double check the line to the solenoid. But with the wiper door open, shouldn't I get the blades to move once I toggle the switch? Makes sense to me because the vacuum is interrupted. Or do you have to have the solenoid functional for the wiper motor to get moving?

After looking at the diagrams in this post, the wiper switch is on right.

Can I reach this solenoid without removing the dash?

Hi sz,
Yes.
Since the wiper solenoid is mounted near the bottom of the tachometer housing it's possible to reach it with the dash pad in place.
Not easy, but reachable.
Regards,
Alan

http://i218.photobucket.com/albums/c...DSC_0544-1.jpg

http://i218.photobucket.com/albums/c...a527d6db4d.jpg

make sure the hoses are connected to the right outlets. I chased mine for a couple days until I reversed them. now my system works great!!!

Driver Dash Panel Vacuum Lines
 

I just put the dash back together and forgot to connect a hose that I had labeled "To Tee" in the car. I remember the Tee in back of the drive dash panel assembly but cannot find it now that I have the dash back together with everything else connected. Anyone have photo that illustrates where I can look? I know it's cramped and awkward to do that from under that dash, but I sure don't want to tear it apart just to connect to that tee.

HELP!!!!

Usually it just needs a good cleaning.

Here's a "how-to" guide:

Wiper Solenoid repair

Hi h,
The hose and T for the wiper solenoid is easy to locate…. if it's where it's supposed to be.
It's on the right side of the tach housing. You should be able to reach up with you hand and feel for the short piece of hose that runs to the solenoid.
Be careful as you put it in place that you don't pull off one of the other hoses. One running through the firewall, and the other running up over the tachometer and speedometer to the wiper switch.
Good Luck!
Regards,
Alan

http://imagizer.imageshack.us/v2/640...923/5c0ucf.jpg