Wiper door issues...

[Stephen B.]

Good afternoon. Working on my 72 coupe which has been over 15 years since it was on the road. Lots of work done here. The issue is when the car is started, the wiper popes open and stays that way till the car is turned off. I tested the vac arm control valve (white dot) and its holds pressure. Vac lines look good and the electric sol valve is connected..... Any clues...tks

[Daniel T.]

Re: Wiper door issues...

My 72 did the same thing and also opened the wiper door at under full load, low vacuum condition. It was the check valve between the engine and vacuum reservoir.

[Gary B.]

Re: Wiper door issues...

I agree with Daniel, it is probably the check valve. If the wiper door stays open while running, it's a gross leak. They, the headlights and wiper door, were designed to stay open in the invent of a total vacuum loss. Look for a loose vacuum hose, or a cracked hose, or check the vacuum tank for a split seam. It could be a hose going to the wrong port on a relay valve or the wiper arm switch, causing a loss of vacuum.
Gary B

[Mark E.]

Re: Wiper door issues...

Good chance it's a bad check valve.