If the system works then you need to retest the vacuum tank for leaks or the one way valve.

If the sytem is the same the tank is not the issue, reconnect everything back to normal
Take your mighty vac and put a T on a hose so you can plug it inline with the yellow line going to the H vacuum switch. Start the car and you will see the vacuuum gauge build pressure. Operate the system and see how the vacuum changes. Then shut off the engine and see if it bleeds down fast or slow. shut off the engine

put everythng back to normal and put the T on the F line, start the engine and see how it works and if the vacuum is the same as the yellow line. Operate the wipers and see how the vacuum changes
put everything back to normal and do the same on the G hose.

What you are looking for is the same readings before and after the vacuum switch there shouldnt be any difference. If there is the switch could be leaking

 

Thanks RR for reply. Will give it a try tomorrow. Thanks

 

no problem, I figure using the vacuum gauge from the mighty vac along with the engine vacuum may help things go faster. I was going for the2 things that are the biggest leakers. IF neither of those pan out we'll start from the one way valve and see if we can see fast leak down somewhere in the system.

 

So far I removed lines from Vac Tank and put in "T". Headlights on but only right door opened. Wipers on door opened and wipers came on but door came down on wipers before they were fully parked. Next step will check yellow line then G&F. Put "T" in yellow line. Had vacuum. Both headlamps worked properly. Wiper door opened a little, wipers didn't come on. Engine off ,lost vacuum right away. Next the red line. Had vacuum ,headlamps worked, Wiper door didn't open ,wipers stayed down. Engine off, lost vacuum right away. Next green line. Hooked up, no vacuum until I turned on wipers but door did not open.

 

Are you writing down the vacuum readings so you can use them to compare to later testing? IF I remember you already tested the one way valve to make sure it isnt leaking back through to the engine, correct? First lets bypass the wiper park/ door switch C to make sure that isnt causing a weird problem just unplug D and using a connector plug it directly into the K hose and run the car and test the wipers to see what happens. It shouldnt be the problem but they do cause problems. If nothing changes just leave it bypassed for now



So what we'll do know is make sure everything holds vacuum when you shut off the motor, first the one way valve, then the tank , then the switch on the wiper side only.
A quick check of the one way valveto see if it holds vacuum.....IF it didnt leak out of the system, test it in the system and see if you can pull a vacuum from the 2 side to the 1 side. Mighty vac on the 2 side, leave the 2 side connected to the system either use the mighty vac or run the motor to pull a vacuum, then shut it off and see if it holds
Try disconnecting outlet 4 and 5 at the tank, and plug the mighty vac into one and plug the other so when you run the engine it pulls a vacuum on the tank. Shut it off and see how quickly it bleeds. It shouldnt at all. if it does you have a tank or line leak.

If it holds vacuum unplug the capped outlet and plug the yellow line goiing to H only into it and leave the mighty vac in the other. This will eliminate the headlight side and you can just check the wiper side. Turn on the engine and using the mighty vac inline see what the vacuum readings are and if the system works or not.
And if you lose vacuum quickly.

If it still loses vacuum then unplug the red and green hoses from the vacuum switch H and plug the outlets to the actuator red and green. Then start the engine and see what the vacuum goes up to. Then shut it off, it should hold vacuum

 

I've editted my lasst post if youve already started just refresh the page

 

OK thanks RR will do. If i remember the check valve was checked and it passed the blow test.I"ll do it again and see what happens.
1.Bypassed wiper switch, wiper door opened didn't close
2. Hooked vac. gauge in line to #2 at check valve Got 15lb. Shut down lost vacuum quickly.
3. At tank. Capped #5 Hooked vac gauge at #4 got 15lb. eng running. Shut down lost Vac. in a few seconds

 

RR not sure if I did this right but updated my post from yesterday.

 

1 When you say wiper switch, do you mean the letter C switch?
2 When you say it didnt close, you mean on the wipers or not at all?
3 On the tank test, unplug the 1 hose and plug that side and see if it will hold a vacuum indefintely while you run the motor for vacuum.

 

So with the system losing vacuum that quickly there is a leak somewhere, so what I want to do is slowly check the hose and system heading towards the light switch. You can follow the hose to each connection, disconnect each fitting and plug the hose then retest with the engine. Leave the tank plugged the way it was earlier so that you are only testing from the engine, through the valve to the tank and back towards the light switch. lets leave the light operating system out of it for now.

each time you get to a tee, you can plug one side and see if the vacuum leaks, then try the other side. that will give yo a direction to go in

 

Yes i meant switch "C". Bypassed"C" started eng. turned on dash switch ,door opened but didn't close when dash switch turned off or when eng. shut down.
Left switch "C" bypassed
Then put vac gauge in line with check valve at "2" got 15lbs. with eng. running and lost vacuum after a few seconds after being. shut down.
Did tank test with #5 capped and vac gauge at #4. Eng, running 15lbs. lost vac. few seconds after eng. shut down. Thanks

 

do this test on the wiper switch C. You're just pulling vacuum on the center connector and it should change from top to bottom when you push the white valve in. And test your mighty vac to make sure it doesnt leak. If neither leak then reconnect the switch. The system working when you removed the switch is pretty telling but the rest of the system shouldnt leak down

http://repairs.willcoxcorvette.com/1...e-valve-works/

 

OK RR I'll check valve "C" next. Do previous tests mean the tank and the check valve are OK?

 

I dont know if the mighty vac is leaking or its in the system. Plug the end of he mighty vac and squeeze the handle to see if it will hold vacuum on itself. If not then we need to get a vacuum gauge from somewhere to see if the tank is holding pressure. the tank shouldnt leak at all. So your system could be good and the vacuum leak we saw earlier in your test could be the mighty vac itself

 

I tested the tank and check valve with the mighty vac and my vacuum gauge with same results.

 

plug all the tank connectors and pull a vacuum on the tank alone and see if it leaks down, and check that wiper switch valve by itself too. We need to see where the leak is. And plug the check valve on the 2 side and pull a vacuum from the 1 side and see if it leaks as well. then we will try pulliing vacuum piece by piece back to that wiper door actuator. the system should hold vacuum ever piece along the way. In the past I had the actuator fail, that actuator relay fail, and my headlight switch leak so you will have your testing cut out for you. Just make sure that mighty vac and the test hoses arent leaking or you'll be chasing your tail.

 

1. Checked Mighty Vac , holds vacuum perfectly
2. Drew vacuum on tank with mighty vac with both #4 & #5 capped , held vacuum over an hour. No leak down
3. Capped #2 at check valve hooked up to Line "K" no vacuum. Hooked #1 in line with "K" no vacuum
4. Next tried to pull vacuum on door switch. No vacuum on either port.
5. Next tried to pull vacuum actuator valve at both "G" & "F" no vacuum.
Also the door switch is not looking very good. The rubber is deteriorated and hard. Loose at both ends. Even if it is good it looks bad. Ordered another one.

 

Im gald the tank held vacuum. When you get that door switch in hook it up and reconnect everything and we will see where the system is. If it still doesnt work well then we can start loooking under the dash more. But if that switch isnt holding a vacuum it very well could have been the issue

 

Thanks RR really appreciate your help. At least I can still drive till the snow flies. Who needs wipers!

 

With everything connected and the engine running, you can try pulling the over ride valve to get the door open or do like you did before and bypass the door vacuum switch, if you ever got stuck in a shower. Or disconnecting the hoses to the actuator you could manually open the door as well.

Let me know when you get the switch ibstalled