genuine1980

I can't seem to figure out whats going on with my system. I am fairly certain that I have no leaks, as every connection I've tested hold vacuum.
I replaced the wiper arm valve and also the relay... test them both too.

Problem now is that the wiper door is not opening when I turn the wiper switch on.

Can the valve on the switch itself be bad?

Mashman

Does it open when you pull the override? The wiper door opens when the control line vacuum to the relay is cut off. The control vacuum cam be cutoff by either the override, or the wiper solenoid. The solenoid is behind the tach. When a current is sent to the solenoid when you turn on the wipers, an electric coil in the solenoid in energized and it pulls in a plunger that cuts off the vacuum. When the control vacuum is cutoff at the relay, an internal spring in the relay expands, and directs the source vacuum to the up side of the actuator.

Its really simple when you think about it.

genuine1980

I think I isolated the problem. The the hose that goes to the relay plunger.... it has vacuum as it should when the overide is off and the switch is off, and when I turn either the switch or override on, the vacuum goes away. However, it seems that even though vacuum is stopped, that the vacuum already in the hose is not being released, thus the plunger is unable to go down... it goes down when I disconnect the hose from the plunger.... I have three relays I tried and the same on each... so I doubt it is defective relay.

I tested this, by running the car... having the hose disconnected from the plunger, I can feel vacuum with my finger when the override and switch is off.... when I turn on the switch or override, the vacuum is not going away on my finger until I take my finger away to release the existing vacuum in the hose.... then when I put my finger back on the hose, there is not any vacuum there until I turn off the override/or/switch again.

What allows the existing vacuum in the relay plunger hose to escape after turning on the override or switch??? It seems that existing vaccum in the hose is not being released even though the vacuum source is cut off by the switch/overide, and not allowing the plunger to go down. If that existing vacuum is allowed to escape instead of being trapped in that part of the system, it would work fine.

Dave J

I won't be able to answer your question until later tonight, but one quick question. Is your vacuum safety switch original to the car?

genuine1980

I don't know what the vacuum safety switch is.

If its the wiper arm switch, then yes it is orig, and i took it out and tested it as part of trobleshooting in this process.... it works as it should "i think"....

0Willcox Corvette

Relay testing
http://willcoxcorvette.com/product_i...ducts_id=27606

Arm switch testing.
http://willcoxcorvette.com/product_i...ducts_id=27607

genuine1980

I do have a new wiper arm switch... but I did not use it after I testing the original and "think" it works fine. plus I heard that the new ones have a manufacturing defect, which is why they are on back order now because the manufacturer stopped making them so they can correct the manufacturing defect....

Could this be the problem?

Dave J

I just tested a "good" wiper vacuum safety switch a couple of days ago. Didn't pass my test. You can bypass this switch to test the wiper door operation by disconnecting the white "top hat" hose on your wiper door relay. Connect a long hose to the top fitting on the relay and with the car running, apply suction to the hose. If your relay and actuator is working properly, you can cycle the wiper door by applying vacuum and releasing vacuum.

genuine1980

Yes, I tested the relay in this way and it works fine.

Still I think the issue is that existing vaccum in the "top hat" hose is not being released even though the vacuum source is cut off by the switch/overide, and not allowing the plunger to go down. If that existing vacuum is allowed to escape instead of being trapped in that part of the system, it would work fine. I don't know what allows the vacuum to escape this hose once the overide or switch cuts off the vacuum.

genuine1980

Ugh... I think I found it. There is a relief vent on the wiper solenoid. I forgot that I capped it when I was testing for vacuum leaks. It's too late here to start the car, so I took the cap off, and first thing tomorrow I will start the car and see if it works now. Wish me luck!

0Willcox Corvette

Just so everyone is aware... The "New" wiper switches are all JUNK!!!! They are made wrong internally and until the supplier makes a change they will not function. We removed them from the site..

genuine1980

All of the vendors have this on back-order until the supplier/manufacturer gets this fixed. And the spare one I had was one of these "Junk" ones and did not work right. I was able to confirm my original one is OK and reinstalled it.

genuine1980

Everything is opening and closing now, all seems strong.

One last issue is that when I first start the car, the wiper door opens then immediatly closes. What's that about?

0Willcox Corvette

The system has a leak... By default with no vacuum the system should open... so when you start the car there is none.. the actuator gets the vacuum first so it starts opening and until the small hose side gets vacuum to pull the relay it will open..... and then close....

Make sense?

Willcox

genuine1980

It does make sense, but I've tested the entire wiper system for leaks that there is none.

Can a leak in the headlight switch actuates be causing this on the wiper side?

0Willcox Corvette

Anything leaking down could cause it.. even a tiny leak.

genuine1980

Its got to be on the headlight side then.

How should the wiper door override work? should it actually open the door? Or does it just keep the door open after shutting the switch off? Meaning that I still need to use the switch to initially open the door.

0Willcox Corvette

Always remember.. the system by default.. works this way..

You block vacuum doors open.. Headlamp or Wiper. You must have vacuum to keep them closed.

So the two over-ride switches.. they block vacuum.. so they will open either the headlamps or the wiper door and it will stay that way as long as it's pulled down blocking...

The headlamp switch.. it blocks vacuum to open the headlamps..

The electrical switch between the two vacuum switches between your legs.. it' cuts power to the motor so you can service the wiper arms.

The tach solenoid.. it's a vacuum blocker... stops vacuum when you turn on the wiper motor...

Willcox

z10kl

So if the door doesn't open with either the switch or the bypass It's probably not the tach solenoid??

Mashman

It could be bad, but there is something else wrong also. The tach solenoid is designed to cut off vacuum to the control line when it's energized, when the wipers are turned on. The override does the same thing - cut off vacuum to the control line when it's pulled. You can test the tach solenoid by pulling the connector off the override. With the wipers off you should have vacuum on one lines leading to the override. When you turn on the wipers, that vacuum should be cut off.

Start the car, and go to the relay under the passenger fender. Pull off one line at a time.

Pull the yellow hose (center larger hose) off the relay, you should have vacuum at the hose whenever the engine is running.

Pull the smaller white hose, this should have vacuum at the hose when the wipers are off, and the override is up.

Pull the red 'down' hose (larger hose closest to smaller hose) , this should have vacuum at the relay port whenever the white lines is not providing vacuum to the relay.

Pull the green 'up' hose (furthest hose from the smaller hose), this should have vacuum at the relay port when the white line is providing vacuum to the relay.