skilew

I just bought a 71 convertible and can't get the wipers to work. The wiper door will not open. Is it suppose to open automatically when ever you crank the car up? Any help will be appreciated.

LoneStarV

No. The wiper door only opens when you activate the wipers. Did you turn the wipers on?

skilew

Yes iI turned it on, could I have one of those switches under the steering column off. The guy I bought the car from did not know what those switches were for, so I am at a loss as to their function. Could someone explain the function of those switches.

LoneStarV

http://forums.corvetteforum.com/c3-t...m-problem.html

Call Willcox Corvette. I think they have a troubleshooting guide for the c3 Vacuum system.

LoneStarV

Btw....do your headlights pop up? If so you know your vacuum is working and it's isolated to the wiper door.

DUB

Those switches under your column are for the headlight and wiper door ( the black plastic pull down pins) The **** in the center is for the cutting off of power to your wiper motor itself.

The black plastic pull down pins are for the manual overrides of your headlight and wiper door. When they are pulled down...they allow the headlights and or wiper door to open WITHOUT using the dedicated switch. One pull down pin controls the headlights and the other is for the wiper door.

If you pull these pins down WITH the engine running and they do NOT open...then you have a vacuum supply issue...or a vacuum hose issue....or bad actuator relays.

When the pins are pushed back up...the headlights and or wiper door should close.

There is an electrically controlled vacuum switch ( located under your tachometer) which is what is used when the wiper switch is switched...to allow the vacuum to go to your wiper door pod....via through a vacuum switch located at the right wiper arm.

I have serviced countless and it is a simple system...once you understand the way it was designed.

DUB

Joelbbvette

Quick testing:

Start car and wait about 30 seconds (in case minor vacuum issues).

Pull both of the vertical switches at base of steering column down. These are the headlight and wiper door override.

Both should open.

If either fails check boots at actuators for tears.

I highly recommend getting a break bleeding kit (inexpensive like Harbor Freight will do) to manually check these systems. Also try to find the Doctor Rebuild book on the 1968up vacuum systems.

They are not very hard to work on but take a little time to understand.


Also if your wiper door opens and the wipers do not come on, the round **** in between the two overide switches at base of steering column is to stop blades in the up position to change them, rotate that before deciding motor is dead. Please don't ask me how I learned this the hard way, but she really was a pretty lady......

Thanks
Joel

skilew

Yes my headlights popup but the wiper door does not.

Where is the actuator boot for the popup wiper door?

Where can I find this doctor rebuild book?

And finally how do I check using a brake bleeder kit?

Thanks for all the responses and help.

71scgc

Dr Rebuild has a laminated diagram for the vac. system. It is very nice, and easy to understand. His wiring diagrams are second to none.
His phone# is (203) 366-1332. 1000-1830 EDT
Carter

Mashman

The below image is from Willcox Corvette, they have put together a great collection of tech documents, and how to's.

In the below, look at the wiper vacuum relay, it is in the middle, and has 4 hoses connected to it.

White - control
Yellow - source
Red - down
Green - up

Yellow should have vacuum on it whenever the engine is on.

White should have vacuum on it when the override is up, and the wipers are turned off. When it has vacuum, the relay should direct the source (yellow) vacuum to the down (red) hose. When no vacuum on control (white) then relay should direct source to up (green).

Red - vacuum when down

Green - vacuum when up

Start the car, and see which hoses have vacuum (one at a time), and that should help determine where the issue is.


http://willcoxcorvette.com/popup_image.php?pID=26609

skilew

Thanks, this will help in trouble shooting my issue.

skilew

Pull the bypass switch for the wiper door and it still doesn't open. Could the wiper switch be bad?

Mashman

No. The override doesn't have anything to do with the wiper switch. If you wan't to check the wiper switch, you can manually open the wiper door by removing the 'plug', and use a screwdriver to manually open the wiper door, by using the screwdriver to push the door open. Once the wiper door is open, the wiper switch should turn on the wipers (when ignition on).

Start the car, then pull the vacuum line off the front of the actuator. That is the down line. Stick your finger on the front, there should be vacuum there. Now pull down on the override switch, and check it again - is the vacuum still there? It should go away, and the relay should be directing vacuum to the back side green/down hose.

If you follow the 'up' and 'down' vacuum lines back under the fender, you will find the wiper relay. The relay has 4 ports. One line is smaller, that is the control line, it should have vacuum on it when the wipers are turned off, and the override it up. It should not have vacuum on it when the wipers are turned on, or the override is pulled down.

The middle larger hose should be in between the 'up' and 'down' lines you traced back from the actuator. The is the source ('yellow') line. If you pull it, and place your finger on it with the engine running, it should have vacuum on it.

With the engine running, pull the up, and down hoses from the relay, put your finger over the ports. With the wipers off, and the override up, then the port connected to the 'down' hose should have vacuum. Turning on the wipers or pulling the override should switch the vacuum to the up port.

If the vacuum doesn't work the way described, then my guess is that you have a bad relay.


**NOTE** I was confused about why you wanted to know about the 'boot'. It's simply a rubber dust cover. I saw a previous bost about checking for a torn 'boot', I think the poster was talking about the diaphram inside the actuator. If it's torn, then the vacuum to the actuator will not do anything. If you want to check it, with the engine off, pull the plug, and push inside to manually open the wiper door. Then turn on the car. Does the wiper door close? If it does, then I think your actuator should be ok.

skilew

One other vac problem that occurred this weekend while I was trying to fighure out the problem with my wiper door I noticed that the passenger side headlight would popup but not go back down.

I kept trying cutting it off and on and then for some reason it went down. If it stays up again how do I get it to go down? And any trouble shooting advice as to the cause would be greatly appreciated.

Thanks for all the help.

Dave J

What you are finding about your "new" car is very typical of many here. It sounds like your vacuum system hasn't been serviced in quite a while, or even not at all in all the years. The vacuum system is rather simple, but you must understand how it works first. Also when you "fix" one component many times that just kicks the can down the road to the next problem. If your components are original, you probably have leaky headlight and wiper door relays, a bad wiper safety switch, leaky actuators, and possibly some issues with hoses, vacuum reserve tank etc.

It's best to learn how to test each component by itself, then string them together until the entire system checks out. If you haven't found it, there is a very good trouble shoot and explanation on the forum. You can find it here.....

http://forums.corvetteforum.com/c3-t...tem-works.html

skilew

Thanks, but for some reason I couldn't open up any of the figures/diagrams. Can these still be open?

Dave J

They open fine for me. Try the pdf link near the bottom of the first post.

Skipper T

Where can i find a good wiper door vacuum switch

Alan 71

Hi s,
Many of the larger vendors carry them... ZIP, Corvette Central, Paragon, and Willcox.
Regards,
Alan

dlux72

1) Go to the Wilcox website and download their pictures of the headlight and wiper door systems. they've got actual pictures of the various devices. This will help you follow the if/then sequence to narrow down the problem(s).
2) Get to know what each component does in both systems.
3) There is a "T" in the vacuum line near the brake master cylinder. This "T" is where both the headlight and wiper door vacuum comes from. I'd suggest you block off the side going to the wiper doors and work on fixing the headlight system first. Then block off the headlight system and fix the wiper doors next.
4) The boots being referred to are inside the actuators. The actuators have rods that are connected to either a headlight door (each door has an actuator) and the wiper door. The rods have what is referred to as a "witch's hat" that is the seal in the actuator to maintain vacuum. I've found that these seals are what causes the majority of the problems.
5) First test: disconnect the green hose on the front of the wiper door actuator and plug the metal connection on the actuator by covering it with a finger (tight), then either manually open the wiper door or disconnect the rod and push/pull. If the door moves you've got a bad seal boot. The same test will work on the headlight actuators.