Winking Headlights and Wiper Door

[Vince C.]

Help! Help! I have read the previous threads on this subject but to no avail. Have a 1969 big block and upon start-up, the wiper door, followed by the headlights both pop up momentarily and then retract once enough vacuum builds. All the vacuum lines are new and routed correctly. Check valve and filter are good. I have checked and double checked all the connections. The system works perfectly as designed while the engine is running. My guess is I have a leaking valve, actuator or relay....??????

While the wipers were sitting idle on the windshield (set the override), I did notice that the wiper arm valve "leaks air" significantly from the plunger as well as the vent (can cover the vent and the valve still releases air). However, I do not notice the venting while the wiper blade is in contact with the valve plunger. Could this be leaking enough in both positions to be causing my problem? I did by-pass the valve by connecting the 2 lines together but had the same result. Should also mention that a few minutes after engine shut-down, the wiper door will lift slightly.

Any ideas? Any simple procedure for isolating and testing individual components? Arrgh......!!!!

Thanks!!!!
Vince
#33415

[Paul O.]

Re: Winking Headlights and Wiper Door

Vince

What you have described is a vacuum leak on the control side. Control side are the small hoses, overrides, relays, solenoid and and switches. The leak could be in any one of those parts very hard to find or several of them.

On the other item you listed when the wiper arm is not parked the switch that is venting at the hose is normal that is to prevent the door from closing if the arm is not parked. But also leaking around the plunger is not.

Hope this helps also if you have a vacuum pump then isolate each item with a vacuum gauge connected to see is that area holds vacuum.

Paul 18046

[Vince C.]

Re: Winking Headlights and Wiper Door

Hi Paul!

Thanks for the insight! I was told to plug the two lines connected to the wiper arm valve rather than nipple them together. This should isolate the one component. Also in the process of borrowing a vacuum pump. Wish me luck...

Regards,
Vince

[Terry M.]

Re: Winking Headlights and Wiper Door

FWIW: My experience, and that of others, is that rarely is there only one leak. These systems will work for a long time with minor leaks, but when the leaks overwhelm the function it is often due to multiple leaks.

[Vince C.]

Re: Winking Headlights and Wiper Door

Hi Terry!

Was hoping for a simple fix but preparing for the worst armed with a vacuum pump. Just purchased the car. Anxious to work the bugs out...

Regards,
Vince

[Paul O.]

Re: Winking Headlights and Wiper Door

Vince

What I would do is have new vacuum hoses just for testing. Connect them to an individual component then test each one for holding vacuum. This way if all the items pass then it is in the hoses or you will find the components that that are bad but it is long, slow and tedious job.

Paul 18046

[Gary B.]

Re: Winking Headlights and Wiper Door

Other things that I find pretty common. The replaceable seals on the headlight vacuum canister shafts, will cause the headlights to wink.
The vacuum switch under the wiper door leaking (or cracked) will cause the wiper to to raise and lower. Other time, the metal 1-into-2 check valve leaking will cause either to blink.
Just replaced seals last week on a set of canisters, solved a lot of other problems...
Gary

[Vince C.]

Re: Winking Headlights and Wiper Door

Can anyone confirm the proper testing procedure for a wiper arm control valve? I have connected a vacuum pump to the center port (which normally would come from the wiper solenoid switch). I have plugged the bottom port with a line that has been confirmed to hold vacuum (which normally connects to the wiper actuator). When the spring-loaded valve button is fully compressed (simulating when the wipers are "parked"), theoretically the valve should hold vacuum. If I release the valve, vacuum should be vented via the top port. Is this correct?

Just checking because neither my existing or new "imported" replacement valve are holding vacuum using the above procedure. Both lose vacuum within 5 to 10 seconds. Is it me or the valve???

Thanks!!

Vince