I have a 72 and the wiper door comes up on start up and stays up even when I shut down. I can push it down gently with car off. Anyone know what is causing this?

I've recently gone through wiper problems, only mine was that they didn't work at all.

For a schematic of the vacuum system go to
http://willcoxcorvette.com/repairandinstallhelp.php?hID=280

or go to willcox for a troubleshooting guide.  look at all their tech helps at
http://willcoxcorvette.com/repairandinstallhelp.php

The system is complex, but not insurmountable you get into it.  My problem was with adjustments on several of the built-in safeguards.

If I were you, I would start by turning the wipers on and then off to see if the door closes (and if the wipers work!.)

Next I would check the two vacuum hoses going to the wiper arm actuator to see if they are split.  I got a complete set of vacuum pipes from Dr Rebuild http://www.docrebuild.com/dr-r-web/DROOPY2.HTML  He's got a good vacuum troubleshooter too http://www.docrebuild.com/dr-r-web/A-TROUBLE.HTML  I bought this, also.

I used both troubleshooting guides as I went through my wipers.

Best of luck, and repost if anything comes up!

Jim

Thank you so much for your help

On the passenger side under the wiper is a small vacuum switch that allows for park setting of wipers. It was bad on mine and allowed all functions to operate.

|UPDATED|3/16/2015 5:52:41 AM (AZT)|/UPDATED|

Yea, once you get all 48 sequence switches to work right, then your door will work flawlessly... 

My problem is after I shut off the engine about 30 seconds later the wiper door opens. I have tried adjusting the wiper door vacuum safety switch and even replaced it but it still opens after I shut off the engine. The system is so simple but can be a real pain to repair.