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Discussion Starter #1
Hi everyone, I work for Retronics Ltd and am new to this forum.

We have a customer who is trying to install one of our intermittent wiper timer modules (RWTM) in their car but the way their motor and switch works is unknown to us and I cannot find any information on the web or anywhere else.

The service information only shows a box for the dash switch and a box for the motor and lines, representing wires, going from one to the other.
I need to know what is happening inside the motor and switch in order to connect the intermittent wiper timer. In particular I would like to know how the self-park mechanism works as the wiper timer interrupts that function.

On many British cars, the self-park switch inside the motor feeds power to the wiper motor via the dash switch (when the dash switch is set to OFF). But I don’t see how self-park can happen that way if there are only 3 wires to the motor and 3 wires to the switch.

The car is a 1971 Alfa Romeo Guillia 1.6 Super Saloon
The wiper motor is a 2 speed, self-parking Marelli TGE 145A, 3 wire motor using a 3 wire dash wiper switch.

Even snippets of information may help as others may know different parts.

A big thanks if you can help.

Matt
 

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Hi Matt,

Welcome on the BB forum.

The self-park mechanism is a disc in contact with the wiper system. The disc has a "missing part".

So, when you put the switch "off", the electric current flows through the disc to the missing area, the wipers then stop.

(missing part of the disc shows with the arrow) sorry for the picture...
Hope it helps.
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Discussion Starter #3
Thanks pescara, it’s good to be here.

And for the photo. Unfortunately this isn’t the info I need, it’s where the wires from the switch go to that I need to know. In other words, the circuit diagram/schematic. I need to interrupt one of the wires from the self- park switch. There are two wires going to that switch, one is power from the battery, the other goes to the wiper motor. We need to interrupt the one going to the motor but do not know which one it is.
 

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Discussion Starter #5
Hi again pescara,

I have realised I am not really asking the right question. As you say, the self-park switch is connected to the wiper motor so as the motor turns, it makes or breaks the switch contacts according to where the wipers are. However, some of the self-park switches I have come across so far, also short the self-park wire to earth when the switch is not supplying power to the motor (i.e. when the wipers are moving and out of the self-park position). In other words, these type of self-park switches either supply volts to the motors coil or they short the coil to earth.

My question is, does this motor's self-park short to earth when the wipers are out of self-park?

I'm hoping that is a little clearer :)
 

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Discussion Starter #6
One more question pescara!
I thought you were talking generally about self-park switches. The photo you show, is that of the self-park switch from a Marelli TGE 145A? If it is, I cannot see how it can short the coil supply to earth as it would need to be a changeover switch and not just two contacts opening and closing. So if it is a Marelli TGE 145A, I think my question is answered. Though it would be good to know then internals of the switch also.
Sorry for all these replies to your post!
 

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Discussion Starter #8
Great, thanks Chris, I'll have a look. The bit that I wonder about is that your diagram shows four wires going to the motor whereas our customer insists he only has three. He says it is the earlier type and doesn't have four wires.
In the meantime, was your photo of the switch from a Marelli TGE 145A?
 

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Bosch, not Marelli. Principle is the same.

You could have with 3, 4 and 5 wires :)

So, 3 wires. The most important thing is to understand what is the role of each wire.

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