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Hi Gerrit,
You describe what some people have called a 'dancing' wiper door.
The vacuum systems for the headlights and wiper door have 2 'sides'.
The 'servo' side is the part of the system that actually moves the doors.
It consists of the actuators, the large hoses, and the storage tank.
The 'control' side of the system determines which side of the actuator ('open'...green hose or 'close'…red hose) receives the vacuum and consists of the switch (for headlights), relays, safety switch and solenoid (for wiper door), and small hoses.
The system is designed to be 'biased' to the 'control' side….
at start up the 'control' should receive full operating vacuum FIRST and thus 'send' the signal to the actuators (servo side) to remain where they are.
If that doesn't happen the 'actuators' receive full vacuum FIRST and open the door (wiper door and/or headlight doors) until the 'control' side relay signals them to close again.
This is because the 'fail' condition for the system is for the doors to open.
For the wiper door look for a leak:
check valve
filter
wiper door relay
small hoses
Hi Gerrit,
You describe what some people have called a 'dancing' wiper door.
The vacuum systems for the headlights and wiper door have 2 'sides'.
The 'servo' side is the part of the system that actually moves the doors.
It consists of the actuators, the large hoses, and the storage tank.
The 'control' side of the system determines which side of the actuator ('open'...green hose or 'close'…red hose) receives the vacuum and consists of the switch (for headlights), relays, safety switch and solenoid (for wiper door), and small hoses.
The system is designed to be 'biased' to the 'control' side….
at start up the 'control' should receive full operating vacuum FIRST and thus 'send' the signal to the actuators (servo side) to remain where they are.
If that doesn't happen the 'actuators' receive full vacuum FIRST and open the door (wiper door and/or headlight doors) until the 'control' side relay signals them to close again.
This is because the 'fail' condition for the system is for the doors to open.
For the wiper door look for a leak:
check valve
filter
wiper door relay
small hoses
Start there and good luck.
Regards,
Alan
That's a great way of explaining those systems I had not heard before. Well done indeed.
When I start the engine, the (perfectly closed) wiper-door opens completely and shut again after an few seconds.
Do You have any idea, where I should search?
Hello Gerrit;
Greetings from Nebraska, USA
Your symptoms are very common on wiper doors. The reason the wiper door opens and then closes normally are caused by a temporary imbalance in the two circuits Alan mentioned. The most common issue is the wiper arm safety valve (or switch if you will) is leaking, allowing atmosphere into that portion of the circuit. This does not allow the control circuit (small hoses) to switch the relay from open to closed before the actuating (large hoses) actuate the wiper door.
You can test the most common component easily. There is a valve or switch under the passenger side wiper arm that allows or blocks vacuum to the wiper actuator relay. Remove the wiper grill. You will find 3 hoses connected to the safety valve. Ignore the top hose. Mark and remove the middle and lower hoses, and connect them together with a short tube of similar size. Start the car, and test the operation. If you are back to normal , you found your problem. If the problem persists, you need more testing. If you do, do you have a hand vacuum pump or vacuum gauge?
Hi Garrit,
Here're are 2 photos of the safety switch under the right side wiper transmission lever.
The first is the hoses you see in the engine compartment
The second photo is taken with the wiper bay grill removed and shows the vacuum switch.
Regards,
Alan
Hi Garrit,
Those are some VERY nice photos of some great looking cars.
Your's is really quite striking!
I bet it really gets lots of compliments!
Regards,
Alan
I realize yours is a 69, but the FIRST 68 I ever saw was a yellow convertible and it really left a mark in my brain! Seeing yours brings back that memory.
I bought the car exactly 20 years ago from Rolf Gersch (well known in the US-Vette-scene as well). Since then, I've added some 40 k miles on the odometer - and had a lot of fun (although it sometimes drive me mad, when something is not working right).
Along the Vette I have some other vintage cars, that I drive during the snowless seasons, so a '73 Volvo 1800ES and a '62 Goggomobil Coupé. Also I keep two '91 Honda CRX VTEC, that make a lot of fun, driving like a go-kart .
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Moving Wiper-Door
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