[kk68]

Got an aggravating issue with my 68 wipers. They work smoothly on low and high speed but when I turn the switch to off, they move to the park position but then just keep cycling in/out of the park and won't shut off. They seem to be trying to park properly but just won't stop. I have checked to make sure that the dash switch and motor (including separate thin strap) grounds are clean and in place. The wiper unit is my rebuilt original. I replaced the original washer unit with a correct repop from Ames hoping that might make a difference but no luck.

Anyone run into this problem and know what the issue might be?

[68ragtop]

I restored my wiper motor a few years ago & I recall there is a mechanism that pulls it to park & shuts off the motor. I'll see if I can find that info. I'm drawing a blank at the moment, but it will come to me once I look at pictures or whatever else I have......
Has something to do with the magnetic coil that holds something until a ground is dropped....... I know they work off of grounds rather than traditional 12v+

[68ragtop]

What keeps popping into my head is if the motor is in high speed & tries to park, it will keep turning just enough to make another revolution & then tries to park again. Something about the low speed wire possibly being disconnected, or the motor turning too fast when parking?

Sorry I can't confirm right now, but if you don't get an answer I will gladly power mine up & help you figure it out while refreshing my memory when I get home this afternoon.

[kk68]

Thanks ragtop! My wipers seem to work flawlessly in low and high speed and I can switch back and forth between high and low with no issues. It's when I turn the switch knob from low to off (park) and it tries to park but just won't shut off and keeps cycling through park mode.

[68ragtop]

Do the blades go all the way to park & then come back up & does the motor pause at all?
There are a set of electrical contact points that are supposed to get opened (or closed) can't remember... when the blades drop down. But only for a moment in the revolution, that's why if they are in high, the motor will pause but keep trying to park.
if the motor never pauses, or pauses very briefly & its in low. my guess is its those points are out of whack. That's assuming the mechanism is trying to park anyway

[kk68]

Yes, they go all the way to park and click like it wants to stop but barely hesitates and then cycles another revolution of the motor and just keeps repeating same. Been messing with this for awhile and a few times it did actually park after cycling several times, but yesterday could not get it to park and had to disconnect to stop.

[68ragtop]

Pretty sure the "click" is just the mechanism going into the park slot, but is independent of what actually shuts it off. I'll bet its those breaker points (contacts) they are supposed to have some wiggle room so the motor can come to a stop when its parked, but it sounds like yours are not staying open long enough if it all. I'll see if I have pictures from when I did mine.

[68ragtop]

I "borrowed" this image from google.

On the bottom you can see the metal arm that is latching to the center mechanism. (kinda looks like an opened end wrench.) When the motor is running that is held away with a electro magnet & when you turn the wipers off, it pops out like it is in this picture, grabs the mechanism. it then pushes into the slot you can see in the plastic (right by the "4")

there is a switch hidden on the other side of that plastic piece that get depressed to shut off the motor. In fact, I think the white wire you can see to the right might be soldered to that switch, you just cant see it.

[Chief of the 60's]

I have one of those magnet switches if you need one. NOS in GM/DR box.

[68ragtop]

Originally Posted by Chief of the 60's

I have one of those magnet switches if you need one. NOS in GM/DR box.

Do you feel up to taking a picture of the backside of that NOS switch? I thought I had a picture of that when I had mine apart & I cannot find it.

EDIT: I found a google picture, it was hard to see the internal switch from the backside too.

[kk68]

Thanks guys. I pulled out an old parts bin and found an old wiper motor I kept for parts.

So we’re talking about this thingamajig? Manual calls it a relay coil and shows the contacts open when wipers off.

[68ragtop]

What book is that? I opened my 68 service manual to 12-25 & its firebird marker lights.

Those contacts are what stops the motor when it goes into park, can you see the contacts? I believe they should be closed in the current position your thingamajig is in.

[68ragtop]

Found a similar diagram in the 68 service manual.
All this searching landed me on a NOS one on ebay at a great price so I bought it as a spare.

[kk68]

I can’t really see the contacts. They seem to be enclosed by the green plastic. I guess this little thingamajig unit is properly called the relay switch. This is not the relay coil currently in my wiper motor this was a spare I found.

Diagram is from the Pontiac 68-69 diagnosis manual, which with your guys help is starting to make sense.

[Chief of the 60's]

Originally Posted by kk68

Thanks guys. I pulled out an old parts bin and found an old wiper motor I kept for parts.

So we’re talking about this thingamajig? Manual calls it a relay coil and shows the contacts open when wipers off.

That is what I have NOS.

[Chief of the 60's]

Originally Posted by kk68

I guess this little thingamajig unit is properly called the relay switch.

GM parts book calls it a "Magnet Switch".

[kk68]

Ok, I think we have it fixed! Great advice ragtop pin pointing the problem.

I pulled the green relay switch or magnet switch out and shot some air down in where the contacts are and poked a little with small screw driver to make sure the contacts would separate. Put the green relay switch back in, held by one screw, and reconnected 3 wires from harness. Turned the ignition key and wipers operated on low then turned switch off and they parked on first try. Ran on low, high, back to low and then off “park” several times and seemed to work flawlessly!

Chief, thanks for offer on NOS relay switch. Looks like I’m good, at least for now.

Thanks again for all the help.

[68ragtop]

My NOS switch came in the mail today. Took a look & it all came back to me without having to tear mine apart

The contacts are normally closed which allows the motor to run, When its parked & off, the lever is pushed in breaking the contacts & shutting off the motor. When you turn the wipers on, the magnet energizes, pulls the lever straight up & in the process releases the switch contacts providing power to the motor again. when you shut it off, the magnet dumps, lever pops outward & grabs the parking mechanism again.

Pretty cool device when you think about it. Interesting that the box on mine is called a magnet.

.

[Chief of the 60's]

Originally Posted by 68ragtop

My NOS switch came in the mail today. Took a look & it all came back to me without having to tear mine apart

The contacts are normally closed which allows the motor to run, When its parked & off, the lever is pushed in breaking the contacts & shutting off the motor. When you turn the wipers on, the magnet energizes, pulls the lever straight up & in the process releases the switch contacts providing power to the motor again. when you shut it off, the magnet dumps, lever pops outward & grabs the parking mechanism again.

Pretty cool device when you think about it. Interesting that the box on mine is called a magnet.

.

Hmmm... I question what is up with yours. Different part number and different color plastic. Mine is 4919641 (old # 4917486). Perhaps yours is not for recessed wipers.

[68ragtop]

Thats very possible. It was not expensive, so not a big deal if its wrong. I thought the recessed part of the wiper was in the gears? I'm Really not sure