When Matthew got his 500F, his windscreen wipers wouldn't park so he asked me to have a look at it.
I'm used to the Lucas wiper motor (I have an MGB Roadster) so I decided to look at how it works before I stripped it down. Even though I'm a Chartered Electrical engineer and have worked on electrics for over 50 years I was slightly bemused at how our Italian friends had solved the wiper parking.
Also I am converting my MGB to intermittent wipe and wash/wipe operation using a VW type 99 Relay (my daily drive is a Golf) and Matthew asked if I could do the same with the 500F so I really need to get a good understanding of the one speed 500F motor operation.
Could one of you more experienced guys have a look at the drawing and explanation and let me know if I have made a glaring mistake.
If it's OK then once I've got the MGB intermittent wipe working I'll mock up the 500F to see if I can get it to work on Matthews.
The Type 99 relay needs a "trigger" which it gets from the Park changeover contacts on the Lucas Wiper on the MGB. The rather more unusual design of the 500F(a simple On/Off) doesn't guarantee my Type 99 design will work on the Fiat.
If the new design works then I'll post it on the Forum with a full explanation.
If it doesn't I'll sob gently in the corner of Matthews garage.

Dear Mattsdad,

Matthew and I corresponded about this very subject a little while ago and I sent him my amateurish electrical interpretation of the mysterious Fiat 500 wiper assembly.

See https://www.fiatforum.com/500-classic/310573-window-wiper-mystery.html

I like your very neat diagram - my messy one agrees with it so I guess I fluked it right

As to your solution, please post it as I and many others would be interested in your upgrade to the Italian electrics. Though I might say that while their wiper solution is not particularly elegant, it is simple and usually does work. I'm not really sure that anything based on a Lucas system would be an improvement

In my garage I also have an old Alfa with similarly arcane wiring for the two speed intermittent wipers and those wipers are still functioning well after many many years. The electrics on my Alfa are Bosch which may go some way to explaining the reliability.

Please don't sob in the corner - it's not very manly and it'll rust both the Fiat and the MG Besides, I'm the one with two old Italian cars - I should be the one crying

Chris

Hi Chris,

apologies for the impersonal title - I should have said that my name is Richard.

I've just looked at the thread you sent and the pictures of the wiper motor you took, and I notice the Park Cam is different to Matthews.
When I dismantled Matthews motor to fix the park I should have taken pics.
His Park switch had a bell shaped contact with a spring plunger.
When the cam moves round the bell drops on to a circular contact to make the circuit to deliver 12V to the motor to keep it powered until it parks.
On Matthews this circular contact was dirty so the motor didn't park.
A gentle rub with 600 grit emery solved it
Your pics also show what looks like the standared changeover contacts as per the Lucas arrangement which would make the MG solution I've knocked together work.
Let's wait until I get it to work on Matthews before I post the drawing.
Also next time I'm over at Matthews garage 'Ill recheck the wiper wiring with a multimeter to make sure the diagram is correct - if anybody out there thinks I've got it wrong or right let me know.
It would also help if the Haynes manual Matthew gave me described the operation in a bit more detail

After going out in Matthews 500 all I can say is
"Fiat 500 drivers - I salute your bravery"

Richard

I hope that's a comment on the car and not my driving style!