Mexico wipers starting on their own!

If the wipers are at all manipulated via the stalk look there.

 

Hi Paul...

I'm thinking maybe a ground issue...

Mike

 

Ivan Ruiz has a pdf file covering schematics for Maseratis 1964-1968. <http://thecarnut.com/Manuals/Electrical_diagrams_1964_1968.pdf>. There are lots of variants shown, but based on your description and the Mexico manual, schema 31 on page 34 of the pdf is probably the right one for your car. There might be a couple of other possibilities: the washer pump switch, or the internal motor contacts that keep the motor running outside the park position so that the wipers park regardless of when the switch is turned off. Good luck - intermittent problems are the hardest to find.

 

Paul,

While you sort it out make sure to remove the fuse when not using the car. The last thing you want is for the wipers to start by themselves in the middle of the night.

Something else to consider is to move the wiper motor to a switched circuit. This way they would only work when the ignition is switched on.

Ivan

 

That's a good one to look at if these wipers work that way.

 

It might not be the evil overlord himself who haunts your wipers. Maybe just a demon he sent by the name of Vitaloni. Be sure to wear a solid protective necklace woven of Bosch relays around your neck when you try to exorcise your wipers. And then some (the Biturbo elder) say that Bosch relays bear the seed of evil aswell...
Your wipers are doomed. Keep out of the rain by all means!

PS: Nice car. Mine has the same colour. Sorry for not being of any help and just cracking jokes.

 

It is still a very beautiful car, even when the wipers go bonkers - nice picture!

 

What is that blue car ahead of yours?

 

TVR....

 

Great looking car that Mexico!

 

nice Mexico but what happened to the chrome around the headlights?

Are you goin for this look....?
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Hi Dirk / Paul...

I noticed that as well, and was going to ask... Attached is a picture
of my car, which is not the best picture, but you can see the chrome
around my headlights...

Mike
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Hi Paul...

Any luck on your wiper issue?

I gave some more thought to this and wanted to check with the experts here, as I
certainly am no vintage Maserati electrics expert! When I read about Paul's wiper issue,
my first thought was grounding. I mentioned this as the wiper circuit would have to be
complete somehow for the wiper motor to do its thing. I could see this happening if the
wiper switch itself completes the circuit by grounding it. If that were the case and somehow
the wiper motor was able to get to ground, the motor would turn. But my quick theory produces questions: 1. Does the wiper switch ground the circuit or provide the voltage to the motor? 2. Is the wiper circuit switched, or supposed to be switched, meaning the key has to be on, before the wiper motor can be run? 3. What about the different speeds of the wiper, how could this be done if the switch grounds the circuit?

I am hoping someone can provide some input into this. I may be all screwed up on this.
But under my scenario, I could see how the wipers could potentially come on by themselves!
What have I got wrong and/or what am I missing?

Mike

 

This is a look at how a typical Lucas wiper motor works. This example is for a single speed but the concept is the same.

The wiper motor has 12 volts going to it. Maserati most likely put the wiper motor on an un-switched circuit, which I don't think is the best way to do it as it leaves you exposed in case of a failure.

The dash switch grounds one of the brushes which makes the motor run. In addition there is a parking switch connected to that same brush. During most of the gear rotation the switch will be closed thereby also grounding the motor. If the dash switch is turned off (as in this image) the motor will continue to run (since the parking switch is grounding the brush) until the gear reaches the point where the parking switch opens and the circuit is broken.

Although possible I doubt the dash switch is at fault. I would look closely at the parking switch. It may be something as simple as old grease drying up and not permitting the switch to fully open.

Ivan
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Hi Ivan.. Good information.. Sounds like I was partially in the ball park in that the switch
grounds the circuit, and if the motor can get to ground by some other means, the motor
could/would keep running. Agree that the culprit here is most likely the parking switch. If it can't get to it's 'off' position, the motor would keep running...

Thanks... Mike

 

In the 64-68 PDF, schematic 8 shows three variants grounded through the switch, and they use either a three wire or six wire motor. Schematics 28,31,35,and 43 show systems with a five wire motor grounded locally through pin 1 of the motor connector. With that clue, Paul could start with the right schematic. I thought schematic 31 made sense because it's the only one that shows both a foot pump and a non-column switch.

 

Hi Paul - just a thought. If your car is wired like schematic 31, then the washer pump switch has a feedback path (orange wire) for the self-park function through a set of contacts that are closed when the pump is not in use. It also has a set of contacts that turn on the motor when the switch is closed (I assume that's when you push a pedal or something). If that switch armature is flopping around loose, it could cause both problems - no self-park, and unexpected wiper operation.