mcs51

Hi there,
In contrast to the early models where motors of windows & sun roof are controlled directly from the switches, from ’90 onward Porsche put a module there.
Attached you can find a, I hope, reading friendly version of the schematic around that module.
Ok, some denominations are in French but that’s good practice for those of you who come to Reims
Anyway:
Left = driver window
Middle= passenger window
Right= sun roof

What bothers me is the way Porsche connected the switches ?? ??
All left controls together on connecter 6 (16)
All right controls together on connecter 7 (17)
One individual input for each button 4 (14) for driver window, 1 (21) forpassenger window and 3 (13) for sunroof

I would expect the other way around
All left & right lines from the switches on individual inputs of the module.
All central connection from the buttons together on 1 input, then to ground.
Ok, that way one needs 2 more input lines but since there are free terminals on the module that couldn’t be a problem

I suppose there is some kind of current sensing circuit in that module to determine what motor to drive and in which direction.

But what happens when you push the switch at pin 4 of the driver window button and the switch at pin 2 of the sunroof button ???
That way both “direction” inputs 6 (16) and 7 (17) are activated together with pin 4 (14) because of the driver window button and pin 3 (13) because ofthe sun roof button.

How can the module know what to do?? ??

Anyone a drawing of the PCB of that module to help me out??

Thanks for reading!
Regards

Alan

It basically only listens to one switch at a time. Depending on direction it may understand multiple (if all in the same direction). The relay drivers also work sequentially - it will only operate one motor at a time in sequence. If you do press open on all the switches together it will remember that you requested all - then process them in sequence. It does this so it can easily detect the stall condition by the rise in motor current, this is more difficult if other motors are also running/starting/stopping at random times (though others can do this well enough). I assume they they connected them in his way to have less wires

Alan

mcs51

Thank you Alan for your insights!
Is “The relay drivers alsowork sequentially” based on knowing the electronics inside the module or an educated guess?
I mean, if only one motor can run at a time, why using a 30A fuse??
Do you have the electronic schematic of that module?

You are absolutely right, they gain 2 wires
But maybecomplicated the electronics a lot


Regards
Alain

Tomkat80222

Now I understand why the passenger window comes down after the drivers side is down if I hit the drives and then the passenger.

Alan

I'm very familiar with the operating mode - and the sequential operation is well known - this is not a guess.

I don't have a detailed schematic of the module - but I know this was a very deliberate decision on their part for the reasons stated - I do agree 30A seems like overkill. The module is microprocessor controlled (well a micro-controller anyway) but drives via SPDT relays in a fairly classic reversing motor configuration. I do have a spare module and have evaluated some of the design decisions and implementation. Given it is Micro-controller based you'd need the code and disassembly to understand the operation fully anyway.

Note this controller has other features you may no know about:

1) If you hold the key in the lock position (in any lock incl. hatch) the windows and sunroof will close in sequence (Pass -> Sunroof -> Driver) for as long as you hold it. You can use this to implement an auto window close system from a suitable KE system (with some risks...).

2) You can modify the USA behavior by unplugging a jumper right next to the module so you get ROW mode. In this mode the drivers door (only) has one touch auto close as well as one touch auto open. Alain you probably already have this.

Also in this mode the windows are enabled (in basic mode) whenever a door is open, normally on a USA car the windows are only enabled when the accessory is switched on with the key and then stay active after the key is removed only until a door is opened. In this mode auto up does not work. This mode is very useful when you are washing the car.

There is another jumper for non-sunroof cars - causes it to skip the sunroof in the auto close on lock - else it waits for the sunroof timeout before moving onto the drivers window.

Alan

ROG100

Be aware that the original module 928 618 240 00 is not recognised anywhere by Porsche.
If you look at PET the number is stated as being 928 618 040 00 but when received it will work but you loose some of the functions as described by Alan in 1) above.
I have been at odds with Porsche over this for a number of years now with no explanation or change.

Alan

This is what the module looks like inside:

As you can perhaps see there is only 1 stall detection system - it is used on all motors - hence the sequencing (one at a time)

Each pair of relays drives a motor: one SPDT relay per motor wire controls the voltage reversing.

Alan

mcs51

Thank you for this extensive information & pictures !
Another µC in that car !!
How many of them did they put in that car ??

1 for the injection (I suppose)
1 for seat memory
1 for the instrument panel
1 for the windows

What’s next… …

ROG100

Alan - Hans ----
Who can make a feasible replacement?

Jim M.

^ or just as important; who can rebuild the units no longer available?

mcs51

Knowing there is µC inside the connection of the switches makes sense!
For sure they sequence 3 output pins of the µC connected to pin 3 of the switches.
Once a signal is detected on pins 16 or 17 of the module the µC knows from which switch it comes since it’s driving the switches

To answer Roger
Everyone knowing µC’s and is able to design / produce a qualitative PCB
Main parts needed:
One µC (e.g.Atmel AT89 series with a way smaller footprint than the actual one )
One ULN2003A to drive the relays from 6 µC digital I/O pins
Six relays
One DC/DCconverter 12V to 5V for the µC
One stall detection system
That is basically all you need

I think of 2 other major problems :
a) Who will take responsibility when people get hurt by closing windows / roof ??
b) Not sure to find such connectors

Alan

Actually likely the only difference between the old full featured module and the newer less featured modules is the code for the uC. Unfortunately it looks most likely this is a mask programmed uC and that makes changing (or getting) the code problematic.

Note that various VW's & Audi's have similar modules - same exact connectors and basic footprint - Depending on the vehicle some do have auto close windows in a similar manner. Would need to evaluate for direct compatibility - but this basic design was reused over and over.

Roger might be worth some sleuthing - we know you are good at that.

Does anyone have (had) a similar vintage 2 door VW/Audi with sunroof with auto close windows on lock... and sequential close like ours?

e.g. here is an example http://www.ebay.com/itm/VW-90-94-Cor...dYEEan&vxp=mtr


Alan

Alan

This thread suggests the VW Corrado windows work exactly like a late model 928 (not sure about the sunroof though).

corrado windows

Seems worth a try for someone... ~$50

Alan

Bigfoot928

I wish I could hit right, left and sunroof and have them all go down at the same time, or all go up at the same time. I know Hans made a kit for a while that would do that.... I wish I had purchased one and his laminated switches too..

Alan

It is a little quirky, and I thought it odd at first - but I'm actually fine with how it works - it really doesn't take much longer.'

There were a lot of European cars of this vintage that had windows controllers a lot like these.

Anyway so who's going to try out the VW unit?

Alan