TedH

I am investigating a problem where my wiper door will no longer go up when I pull down on the switch under the dash (wiper door and wipers have had a synchro problem which I have been using the under-dash switch as a work around ever since I bought the L46 in Jan '05). Also, the headlights are VERY slow opening and I have to open them by hand AND the wipers will not operate when I slide the wiper switch to the right.

I may have a vacuum hose leak or a broken vacuum fitting. I am going to trace each and every hose this evening. Wanted to see if a wiper motor failure could affect both systems as the wiper motor won't even drive the wipers if I open the wiper door by hand.

NOTE: I recently installed the blueprinted/rebuilt distributor after having Lars work his magic on it and the carb. I am focusing on that area as I had to move alot of wires and hoses near there when I removed/installed it.

Thanks for any info!

TedH

UPDATE: Have pulled 'How to Restore and Modify Your Corvette 1968-82' from the shelf and am studying Ch 15 'Vacuum System' in prep for my investigation...

TedH

OK,

First, I checked the wiper fuse; it is intact.

Have re-connected a vacuum hose that attached to the lower port on the vacuum relay that mounts to the firewall above the master cylinder. Apparently, I had nudged it loose when I was moving wires out of the way of the distributor.

Also, found a rotted hose that attached at a 'switch' mounted to the driver's side of the wiper motor. The hose ran to a 'Y' tee that feed what appear to be the windshield washer ports.

Checked all hose connections at headlight actuators and the front relay. Headlights now open and close on their own (but slow... they have always been slow). I suspect I have some inner/outer headlight actuator seals to replace.

Regardless of the position of the passenger side override valve below the dash (the left override valve will cause the front headlights to open without turning on the lights), the wiper door will no longer lower itself. I have checked it and it appears to be hanging up somewhat on the driver's side hinge. WD-40? Also, there is a black '****' between the two vacuum override valves that turns about 1/4 of a turn left and right. What is the purpose of this? It doesn't appear anywhere in my service manual.

Also, there is what appears to be an exposed contact (relay?) mounted on the firewall to the right (passenger side) of the wiper motor. It appears to be actuated mechanically as it has two (contact?) surfaces that are about 1/4" apart at this time.

At this time, I'm thinking one or a couple of the following:

Wiper switch failure
Wiper motor failure
Wiper door hung up and somehow caused by the other two wiper component failures.

Question: How do I test the wiper switch and/or wiper motor for actual failure? Is there a continuity (ohms?) test procedure to validate failure of either component? Diagrams for testing?

Wiper switch appears very loose at the different stops (off/intermittent/on).

TedH

I will study this thread this evening to diagnose my wiper door staying open.

http://forums.corvetteforum.com/show...tor&forum_id=3

NOTE: I opened the wiper door manually recently when it failed to open when I pulled the override valve to open the wiper door. Only after opening it manually did I also find the wipers inoperable.

The wiper door has never had the best timing when using the wiper switch to open both (should I ALWAYS open the wiper door using the override? My impression is the override valve is meant to OVERRIDE normally opening the wiper door via the wiper switch signal.

I believe more and more that I have a wiper switch issue at a minimum and will test the wiper door relay and actuator also. NOTE: The wiper door relay IS the original, 37 year old relay.

yukon988

What year is your car? I'm guessing '69 from your photos. The vacuum system varies a bit from year to year and I am most familiar with the '72. I am also guessing you have at least 3 different problems:

1. Headlights operating slowly -- could be vacuum relays for headlights, vacuum actuators for headlights, or just not enough vacuum. Does your canister hold vacuum after you shut the engine off?

2. wipers/wiper door timing -- What exactly do you mean by that? If you mean the wipers try to run before the door opens AND the wiper door closes before the wipers stop, it may be the switch on the firewall operated by the wiper door linkage (not sure if this is on the '69). If the wiper door is just slow like the headlights are, then maybe you just are not producing enough vacuum.

3. Wipers not working -- must be electrical. Could still be the switch on the firewall I mentioned in #2. If that switch gets stuck closed, the wipers wouldn't come on. I would suspect other things though before that. You didn't disconnect the ground by accident when you were messing with the distributer, did you?

TedH

Correct, it is a '69.

There appear to be three wires that connect to the wiper motor. Two connections are opposed to each other on/under the front cover of the wiper motor and another connects to a strip of metal on the upper right (10 o'clock) of the wiper motor (facing the wiper motor from the front of the car). All three wires appear connected properly. If there is another wire, I am not seeing any dangling wires.

Wipers/wiper door timing - Prior owner emphasized that wiper door MUST be opened via the override valve before turning on wipers. If I were to only rely on the wiper switch, he said (and demonstrated) that the wipers would collide with the wiper door before it could be fully opened. Therefore, it appears there is some timing issue between the operation/opening of the wiper door and start of the wipers.

Could the switch on the firewall be the mechanical contact or is it an electrical device (picture?). I can take some pictures and email them to you if necessary.

the vacuum door controls/items I want to investigate from my chassis service manual:

- Vacuum actuator
- Relay vave
- Interlock valve
- Vacuum override valve
- Vacuum control solenoid (appears to be electrical. this may have failed previously and necessitated the use of the override under the dash...)

Milest

My wiper system had problems and I was able to get them worked out after I bought the car five years ago.

This the way I understand the wiper system and how mine functions on my 72. Don't take it as absolute, but I think I am pretty close. Let this topic sit and other members will chime in and help explain how to get your problem fixed. Your approach is great!!!!!!

The black **** is so you can stop the blades in motion so you can change them. When the wipers are functioning normally they "hide" (under the wiper door) when the console switch is off. When you turn on the console switch the door opens, the wipers move and go back and forth. When you turn the switch off the wipers fold down and "park." After the blades "park" the wiper door closes.

Good luck and keep at it.

yukon988

Your motor sounds a little different than mine. I wonder if it is a '73 or newer motor without the controls for the wiper door. That's what was on my car when I bought it. If it is the correct motor, there should be about a 5" long red wire coming out the right side. This is the main power and goes over to the electrical switch on the firewall. On cars without wiper doors, the motors don't have that red wire. You can see the wire in this picture (although its painted black) http://www.ecklers.com/product.asp?p...dept%5Fid=1317 coming off the top going to the left.

Also, on my motor, there is a connector with 3 wires. These wires control the motor speed. Next to those, there is a connector by itself with a big black wire (ground) connected to it. On my motor, if you disconnect the 3 wire connector and connect the red (power) wire to 12V battery power and the black wire to ground, the motor will run and the wipers will move. That is one way you can check to see if the motor is working.

Another thing that makes me think you have the wrong motor is because of what the previous owner told you. If the motor was replaced with a newer one, you would have to use the manual override to open the wiper door.

By the way, before I forget, if you do end up deciding you need to get a new motor -- Autozone is way cheaper than the link I used above to show you the picture.

Also, I will PM you my e-mail address if you want to send me some pictures. I don't have access to a digital camera right now so I'm afraid I can't send you any.

LGHTSPD

TedH,

I have a 69 also and just completed fixing the same problems that you're having. May I suggest that you check the following things:

1. The wiper door must be full forward to contact the wiper safety switch. If it is not, the wipers will not activate. This switch is located on the firewall just above the distributor and is activated by an arm that is attached to the wiper door mechanism.

2. Check the integrity of the wiper interlock valve, which is located at the base of the right wiper arm. This valve has 3 vacuum lines attached.
Replace this valve if the housing is cracked or the boot is torn.

3. Make sure that the 2 bolts that hold the wiper door actuator are not tightened down. They must be left loose enough to permit the actuator to pivot as the pushrod operates the wiper door.

4. Check all vacuum attachments at the main relay valve (it may be on the right fender or on the left firewall depending on month of birth) and all other vacuum hose ends, i.e. where the hose connects to the intake, vacuum filter, check valve, etc.

5. Check the wiper solenoid for no vacuum leaks and proper electrical function. It is located on the rear of the tach and can been seen easily by looking up from the accelerator pedal.

By some of your problem description, I suspect that the interlock valve is not working since the previous owner said that the wipers will not cycle properly.

In re-reading your post, it appears that you have the correct wiper motor. The description that you give of a third wire going up to a metal strip facing towards the motor, that is the wiper safety switch that I referred to. It is a safety device that will not permit the wiper motor to turn on until the door is full forward. If that switch is not activated by the arm on the door mechanism, the wipers will never turn on.

Keep us posted on your progress.

Mike

c69vete

On 69s there is a wiper parked switch under the wiper door. this switch is to prevent the door from closing before the wipers have parked. It is on the passenger side. It has a white button on top and a rubber bellows that will rot and leak vacuum.

TedH

All,

Thanks for the excellent guidance. I'll continue my troubleshooting with a printout of it this evening.

TedH

QUESTION: Is it possible to easily remove the wiper door cover in order to diagnose the wiper motor/switch/door assembly issues?

Please advise.

NOTE: I am consulting my book 'Corvette Weekend Projects' by John Pfanstiehl for his guidance on wiper door removal and alignment. I see there are shims and alignment considerations so I'll be watching for any adjusting shims on the mounting points of the door to the assembly.

yukon988

There are 4 bolts that hold the wiper door on. Those bolts are usually rusted and extremely easy to break off. Once broke, the wiper door is a little tough to fix. If you are going to remove those bolts, make sure you soak them good in WD-40 or whatever before you do.

TedH

Found that a vac hose interfering with the wiper safety switch. It passes through the firewall with two others nearby and happened to be lodged in the way. Once I moved it, the wiper safety switch made contact and I can now operate the wipers at all speeds.

So, no need to replace the wiper motor or wiper switch (yet).

The headlights are still lazy (as they have always been since purchase). I am going to take a closer look at the vac seals on both headlight actuators. I suspect a need to replace on both as the headlights open/close very slowly.

One of the four (4) wiper door bolts is stripped out at the front passenger side corner of the wiper door. It threads in but never tightens. It had fallen out along with its nylon bushing; I found both and tried re-installing. I may try a good thread locker on Weds.

The wiper door does not open or close on its own. I can raise/lower (carefully) and have WD-40'd all pivot points of that assembly. No apparent hangups.

I will read through the thread and my info on the wiper door air circuit to see if one of the actuators or valves is suspect. One other item, the hoses all are a bit 'loose'. Unfortunately, I cannot take much material off of the ends of the hoses (between the wiper door actuator and the relay) without running short on hose. I may opt for a fresh set of headlight/wiper circuit hoses and connectors.

I am not certain that the vacuum chamber has integrity. I have to run the car for about a minute before the headlights will respond to the on/off switch. It appears to build vacuum but if I turn the car off, there does not appear to be residual pressure. Again, seals at the headlight actuators, and the hoses that run within that air circuit may be a big help.

TedH

How do I determine if the wiper parked switch has failed? If it does, will it prevent a signal and result in the wiper door not opening or closing on its own? I may try replacing it.

LGHTSPD

If the interlock valve has failed, the wiper door will not operate properly. Most likely you will also have a vacuum leak which you will notice in slow movement of your headlights as well any other vacuum operated system.

Doing a visual check, what is the condition of your interlock valve? Is the rubber bellows cracked, torn, missing? How about the white hard plastic cap that should be on top of the bellows...is it in good condition?

Replacing the valve is a relatively inexpensive project. Average prices are apx. $25 plus shipping.

Mike

LGHTSPD

>>The wiper door does not open or close on its own. I can raise/lower (carefully) and have WD-40'd all pivot points of that assembly. No apparent hangups.<<

A couple of possible culprits here...the wiper solenoid is not sending the vacuum signal to the wiper door to open and/or the wiper door actuator needs work.


>>I am not certain that the vacuum chamber has integrity. I have to run the car for about a minute before the headlights will respond to the on/off switch. It appears to build vacuum but if I turn the car off, there does not appear to be residual pressure. Again, seals at the headlight actuators, and the hoses that run within that air circuit may be a big help.<<

More than likely, this is your vacuum leak at the interlock valve. Mine did the same until I replaced the valve.

Mike

TedH

Is the interlock valve the same as the wiper door parked switch?

yukon988

Do you have a hand held vacuum pump and/or a vacuum guage? Also, do you have vacuum on either side of the wiper door actuator (and if so, how much)? Given that the door will not open and the headlights raise and lower slowly, you might have a vacuum leak on the "power" side of the vacuum system (the side that does the work of opening and closing things). Have you checked the check valve yet?

LGHTSPD

Yes.