Investigation and an temporary solution - www.AudiV8.com

This weekend I did a big investigation of how the Power Window Control Unit realy works.
I began with making a multi wire so I could have the PWCU up from the floor an so it would bee easy to disconnect and measure each pin.
I also found some websites with information of how non European Audi owners replaced their simplier PWCU 443 959 257 A with the European D model so they could get more intelligent windows operations.

This is PWCU major functions :
-Supply all windows switches with 12V under different conditons .
-Act as an automatic main switch for driver windows , just as driver has main switches for the other windows.
-There is also some other functions as automatic closing all windows an something that deal with anti teft system that I haven´t figured out yet.

The 12V supply to switches works like this:
When ignition goes on 12V comes to PIN15 then 12V PIN30 goes out to switches by PIN87 .
A timer starts counting down an if not the engine or any switches i touched then 12V out from PIN87 goes down to about 0,3V . (It can bee seen as the light in switches goes off or if measuring current it goes from 0,2A to 0,01A)
As soon as any switches is touched the 0,3V change to 12V and the downcounting starts again. If the engine is running 12V comes to PIN61 and PIN87 output is 12V all time
This is going on until the ignition is off and the drivers door is opened and closed again , monitored by PIN TKI , then output to PIN87 is off.

This is something that sometimes doesn´t work on my PWCU , when it goes down from 12V to 0,3V it hangs in the middle and starts buzzing. In this state it is difficult to get it right again .
It doesn´t help take power or/and off for a short time and it can suddently begin ticking with the other relais in it to. I also once had it staying in 12V state all time to , no mather igition , running engine , door signals.
I haven´t found out what makes this bad state .

The automatic switch for driver window works like this:
There is two input PIN85 and PIN86 that give information of if the driver window switch is activated by the driver. ( it check the voltage each side of window motor )
There is two output PIN87A and PIN87B that can have 12V or GROUND depending if the PWCU wants to run window up or down.
Automatic running can start by tapping window switch , tis is detected as 12V on one of PIN85 or PIN86
If the window is automatic running and the switch is tapped the other direction , then window motor gets 12V on both sides , detected by PIN85 & PIN86 and automatic running can stop.

This automatic running have some conditions to work , and I am not realy sure of how , my owners manual is in German and I can´t understand it so good , and it seems that my PWCU dont act the same all time.

The other function is:
Automatic closing , 12V from PIN87 goes thru an Automatic Closing Realy and is grounded at PINKR , this ACR change the ground wire to 12V to all windows motor except for driver window , that can be controlled by the automatic running function.
How to start this process I havn´t found out , also this by my bad German understanding . But I found out that it an Fuse was missing , Tis fuse wasn´t in the "fuselist" but was located , almost hidden, above all the other fuses ,

Due to the doubt function of my PWCU I desided to not use it . Instead I used a simple relay that gives power to window switches all time engine is running ( could used igition on instead ) . I also had to ground connections from driver windows motor.
This is the connections I made in PWCU socket:
PIN30 by relay switch to PIN87 , activated by PIN61 (or PIN15) through relay coil to ground PIN37 , PIN 87A and PIN87B also to ground PIN37.

Now I have main function on windows and I hope I don´t drain the battery any more. If I find any PWCU on an junkyard in the future perhaps I try I but will not buy another new one.

If anyone have the english version of the owner manual , I would like to read the section of how the power windows automatic running and closing should work

Bengt

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