Sorry, I know this has been beat to death, but I'm out of possible solutions:
1971 454 coupe. Headlights open & close perfectly. I have replaced the actuator seals, filter , check valve & wiper relay vacuum switch (all bought from Zip ) The door opens about 1/2 way, then the wipers begin to rise, hit the door, then continue onto the windshield. Turn off the wipers & everything returns to the correct parked position. I've tried changing the adjustment point for the actuator rod, but no change. I can pull the door up by hand to the same position as it reaches with the switch, then the remaining distance feels some resistance. The door just doesn't open enough to fully clear the passenger wiper arm.
I've read about the questionable vacuum switches & the good one offered by Dave, but would appreciate your help before throwing more money at this problem. Yes, I have a Mity Vac & vacuum gauge.
Thanks for your help.

 

Maybe binding at the hinges on each side? Think I would unbolt the door and inspect the hinges. These bolts can be rust frozen though... hope yours are not! Maybe rusty hinges too?

 

Hi Tim,
Is the door not opening fully or are the wipers starting before the door is fully open?
Perhaps the wiper door safety limit switch needs to be adjusted.
The 'plunger' on the door linkage should be adjusted so that the wiper motor doesn't start until the door is fully opened.
Regards,
Alan

The switch and plunger.


The adjustment nut on the threaded shaft of the plunger.

 

The door stops opening, then the wipers raise-up & hit the door. I've adjusted the actuator rod to 3/8". I'll try 1/2 - 3/4" to see if that works. With the actuator removed, the door moves freely. I might have the rod adjusted too short & its hitting its limit before it raises the door completely.
I'll keep you informed. Keep the suggestions coming.
Thanks, Tim

 

Hi TW,
The limit switch completes the wiper motor circuit.
The wiper motor can't start until the button switch is depressed by the plunger.
If you back the plunger all the way out on the bracket the wipers would never start no matter how far the door opens because the circuit wouldn't be completed.
Are the wiper arms bent or are there aftermarket blades on them that are causing the arms to hit the door?
Regards,
Alan

 

Have you operated the actuator without it connected to the door to see if the rod will move all the way to the full extended position. I have a new looking one that binds, and you can see where the can rubs the rod. It may not be extending all the way.
Measure the rods extended length connected and disconnected. If its extends further disconnected then it could be the limit switch arm.

You said the door moves freely with the rod disconnected. Does the wiper hit it when its openned by hand? Adding to what Alan said, if it does its the door open limit switch plunger that hits the limit switch , its adjusted out too far. If this is the issue, I moved mine to its shortest position, opened the door all the way with the vacuum, then adjusted the plunger out until it activated the switch.

Alans second photo shows its adjustable
http://i218.photobucket.com/albums/c...6/DSC_0202.jpg

 

OK, here's what I've found:
1. Set the actuator rod locking nut at 1/2". Rod moves freely.
2. Completely removed the Safety Limiter Switch plunger so it never depresses the switch.
3. With the engine running, turned on the dash wiper switch & wipers crashed into the door again.
4. With the engine off, ignition on, pushed the dash wiper switch and the wiper arms contacted the door. ( door was closed )
5. With door manually open, pushed the dash wiper switch & the wipers came up & made complete sweeps. Cancelled the dash wiper switch & the wiper arms went back to their correct parked position.
6. With door manually open and wipers sweeping, pushed the Safety Limit Switch several times with no change.
** Is the Safety Wiper Switch defective ? I feel like I'm getting closer to a solution thanks to you people narrowing the search. What do I do next ?
Thanks, Tim

 

Hi Tim,
With the plunger removed the wiper motor should NOT start.
Depressing the button on the switch completes the wiper motor circuit.
Can you feel the switch button 'clicking in and out when you push it with you finger? It may be stuck 'in'.
Regards,
Alan

 

Yes, the switch button is clicking. But no change in the wiper action. That's why I think the switch is bad. After 45 years I expect there will be a few failures. Tim

 

Hi Tim,
Even if the switch is causing your problem I would test the operation of the door manually.
I don't know if you've done that or not.
Remove both hoses from the wiper actuator.
Remove the rubber plug from the front of the actuator.
Look in through the hole and you'll see the metal diaphragm inside.
Using your finger or a screwdriver reach in through the hole and CAREFULLY push the diaphragm as far as you can (1" or 1-1/2") and see if pushing it opens the door completely.
It should.
This will tell you if any of the linkage is binding and if the adjustment on the actuator is correct enough to fully open the door.
Regards,
Alan

Push this direction to open the door.
After opening the door you can safely close it by cycling it with your hands to the closed position.


What matters is NOT how high the door LIFTS but rather how FAR FORWARD over the wiper bay grill it moves. You can determine that by manually operating the actuator.

 

Latest Update:
* With the door opened manually, I completely removed & disconnected the Safety Limit Switch from the car.
* Turned on the ignition & pushed the dashboard wiper switch. The wipers were activated, swept the windshield & returned to the parked position when I turned-off the dash switch.

Now I'm really lost. I was hoping it would be a faulty limit switch.

HELP !!

 

When you said the door was manually open it worked. Did it contact the door? The limit switch just prevents the wipers from opening until the door is fully open. On a 68 system, the wipers shouldn't work without the switch, guessing its the same as a 71 except the 68 is negatively switched, so something is wrong there.

If the wipers dont hit the door when its manually opened all the way then you just need to adjust the actuator arm so it opens that far, hopefully it closes fully.

The limit switch is a different problem. I dont know the 71 electronics, hopefully Willcox will chime in. You can check the wiper troubleshooting on his website, maybe Im wrong about how it works but I'm not betting on it.

This is how far mine open

 

Hi Tim,
Does the wiper interrupt **** under the steering column stop the wipers in mid-sweep?
Regards,
Alan

 

Alan: Haven't tried that. Is that the larger round one in the middle ?
Rescue Rogers: My problem has been that the wipers are activated as soon as I turn on the dash switch. So, they tangle with the door & I'm unable to determine if that is limiting my door opening. I wanted to clearly identify that the wipers were out of control by removing the safety limit switch & not turning on the engine ( thus eliminating vacuum activation of the door ) hoping that the wipers would not turn on. Then I could determine if, once the wipers were dead, the door would actually open fully. But that plan went bad when the wipers kept wiping.
I'm trying to isolate the vacuum & electrical systems. Obviously, I'm not doing very well at that. With the safety limit switch disconnected, how/why are the wipers able to work ?
Discouraged Tim.

 

Hi Tim,
Yes, the **** between the vacuum overrides for the headlights and wiper door.
Regards,
Alan

 

Im sorry, I understand now. Look up Willcox wiper bench test. You can do it installed in the car. It will test all functions of your wiper motor. I think if you disconnect the wiring and test it, it will pass everthing but there is a chance the wiring could be crossed inside the motor that allows it to work when the limit switch isnt connected. You can test your limit switch with an ohm meter.

If the motor is good, you willknow its part of the wiring, maybe your wiper relay is stuck and its giving you all your power all the time. I would start with the easy and obvious then get into the hassle of wires

If I remember correctly, in my car, the wiper switch energizes the system and activates the vacuum relay behind the tach, the vacuum goes to the actuator valve and makes the actuator open the door, the door pushes on the limit switch closing it, which sends a ground(68), power in your case, to the relay under the console which closes the circuit for the wiper motor allowing it to turn on.

Either you have a crossed wire inside the motor giving it power all the time or maybe that relay is frozen and it gets power all the time, last possibilty is a short that gets power to the motor all the time

Hope this helps. Maybe Wilcox or Alan can clarify for a 71

 

Alan71: With ignition turn on, but engine not running. Wiper door open manually:

1. Ignition on, tuning wiper interrupt **** does nothing.
2. Ignition on, dash wiper switch in low position. Wipers sweep. Turning interrupt **** does nothing to change wiper action.
3. limit switch checked OK with an ohm meter, but has been removed & unplugged .

What next ? Thanks for your patience with me. Tim

 

Hi Tim,
The **** under the steering column is designed to interrupt the wiper motor circuit.
The safety switch is designed to complete the wiper motor circuit.
It seems the only possibility is that the wiper switch is wired directly to the wiper motor.
Have you looked at the wiring on the switch and at the wiper motor to see if it's been modified?
Regards,
Alan

 

Alan71: Yes, I discovered a toggle switch under the dash that the P.O. used to turn on the wipers. Apparently there were 2 related problems that he didn't recognize. The wipers that hit the door & they were activated too soon. He eliminated one of them with the switch.
The second was that the door was not opening far enough to clear the wipers. I've discovered that the actuator rod sleeve nut was bottomed-out & not allowing the door to open fully.
How far out should the sleeve nut protrude from its housing when the door is closed ? Measured from the lip(protrusion ) or the face of the box ? This will FINALLY cure my problems and I can rewire the wipers when I have more time this winter.
Thanks for everyone's help. This Forum is invaluable. Tim

 

Hi Tim,
That's good news!
The info on how to adjust the nut is in the AIM UPC1 asm, Sheet D4.
Note that it describes the position of the door and the actuator when the distance is set.
Regards,
Alan