How does the wiper mechanism work?

[Pope1]

It's been so long since my car was in proper use that I cannot remember how certain things are supposed to work.

I thought that the wipers had the normal auto-park feature where they would return to the rest position regardless of where you turned them off.

At first, when I got the car going the wipers would not auto-park. Ok, no problem, just turn them off at the relevant point. Then all of a sudden they decide that they want to auto-park in the middle of the screen. OK, no problem, re-position the wiper arms. Big mistake the wipers then try to wipe the bonnet at the bottom of their travel.

So my question is does anyone know how the auto-park facility works( assuming the car is supposed to have one)? Is it controlled by the switch, by some electronic box or by something electrical or mechanical that is part of the wiper motor? I have a spare motor so I can change that if
necessary. Just not sure of the best place to start on this one.

I'd be grateful for any suggestions guys. Thanks.

Chris

[A1.6HPE]

Hello Chris,
The self parking function is provided by having complicated switch wiring/contacts and set of contacts in the motor gearbox. Usually it is the contacts in the gearbox that corrode, so changing the motor should fix it. However, I don't understand how your wipers started parking in the screen.
You could plug in your spare motor and observe its operation (without connecting it mechanically), perhaps a cardboard pointer fixed on the shaft so that you can see where it parks. That would easily identify if the motor was the problem. Could be the wiring at the connector of course.

Good luck, Leo

[John Allen]

The wipers will stop in the middle of the window if the auto-park contacts are not working AND if the wiper control is set to 'intermittent'. The time delay on the intermittent setting stops supplying the power to the motor before it reaches the end of the wipe.

-john allen

[Pope1]

Guys,

Many thanks for your information. Much appreciated. Leo, you've given me a great place to start and John, you have filled in a missing piece of the puzzle. You are absolutely correct, they were on intermittent. The only thing is that after having the car off the road for more than 6 years I had forgotten that setting I is intermittent and with the light spattering of rain that we had yesterday they were never on long enough for me to realise that. :roll:

Chris

[Will]

....bet you'll find the "arm" of the park switch has rotted completely from its mount. I've seen a bunch like this.
Unfortunately, reduction gears are not interchangeable between models. However, the park switch and housings are in some cases- for instance, the Beta Coupe and Montecarlo use the same housing, with the wiring connected differently.
I've just done this recently.
-Will

[Pope1]

So far it's been interesting. Took my spare off the shelf and opened the gearbox to see what the mechanism look like. Inside it looked as if it was brand new. Very, very clean gear and switch in immaculate condition. Not what I was expecting because the spare one sat outside in a car for far too many years and was generally in much worse shape than my main car.

Looked at the main car. The wiper motor has a plastic cover wrapped round it to protect it from the elements. Not sure if this was standard from the factory or added by a previous owner. I could not get it off properly without removing the retaining bolts for the motor and I did not have time to do all that today. However, a little peek underneath showed a motor that looked brand new based on the little spot that was revealed.

Checked the red connector block that feeds power to the motor. This had the most filthy spade connectors I have ever seen in my life. I'm surprised that there was no vegetation growing in there! Removed each one individually and carefully cleaned it with some fine sandpaper. Put the connector back together, turned on the ignition, then the wipers and... they are still doing the same thing. :x So the motor will have to come out for further investigation in the next day or two.

[Will]

...the plastic "rain jacket" is stock. Yes, the three bolts pass through it.
The design weakness is the hollow cavity where the parking switch sits, which rides on the lobes on the reduction gear (behind the toothed wheel).
This hollow cavity can retain water. Many of them are SUPPOSED to have a wep hole in the bottom, but depending on the conditions, it seems it lets water in better than out sometimes.
-Will

[Pope1]

Thanks for the wealth of information guys. I think that I've fixed it but I will not be 100% convinced until I've done some further testing. It seemed to be a combination of things, namely:

1. Intermittent connection problems from the dirty terminals in the loom connector.

2. Incorrect alignment of the arm that is connected to the motor.

Once the electrical connectors were cleaned up the arm was auto-parking but in the wrong place. Unbolting and re-positioning the wiper arms was no good because the position of the motor arm was such that the wipers would always move below the bottom of the windscreen during the wipe cycle.

I don't even remember taking off that motor arm but I must have done it at some stage during the car's rest period.

Oh, and the auto-park switch and the internal gubbins in the gearbox? They looked like brand new after 20 years, with no sign of water contamination or corrosion of any sort. Maybe that plastic rain jacket really does work after all.

Chris

[A1.6HPE]

Well done Chris. I guess that your car has not seen much wet weather. When I opened the gearbox on the wiper motor of my Montecarlo it was full of rusty water! So the rain jacket didn't help that one much. However the connector was OK - that's Lancias for you!

Leo

[Pope1]

You're so right about the variability of Lancias. Tis true my car has been indoors for the past 7 years but I don't think it had a pampered life before.

I figure that as long as the rain jacket is intact and the scuttle where the motor lives is never allowed to fill up with water, they should be OK. Maybe other cars have experienced periodic flooding? The other weird thing is that my spare motor came from another VX that I bought for spares. It sat outside in my garden (covered by a tarp most of the time) for at least five years and was in a dreadful state in the end. So much so that I lost a number of items through neglect but that motor also seems to be in excellent condition. Go figure! 8O

Once again, thanks for your suggestion Leo. It was only when I put a pointer on the wiper shaft and operated the wipers with the mechanism out of the car that I managed to figure out what was going on.

Chris

[Will]

Leo:
I think you'll find the Scorpion/Monte wiper park switch is affected most of all, and I think it's due to either the orientation or the grill being right above, but notorious in that particular model. The scorpion owners here in the US have replaced plenty of them. I found the reduction gear on that unit appears to be unique also, and has a multitude of smaller pitched teeth as compared to a normal gear. This would be in an earlier car, say a Scorpion or a S1 monte. I'm not sure if the S2 montes were using the better gear, which was used on the Early '80's cars here (Zagato to us, Spider to you).

-Will