window module for mercedes

Am trying to install a window closure module to my 2002 mercedes A class but the operating power signals from the car's switch and at the motor end are very low 1.8v to 1.9v,any ideas as the window module sends either 12v+ or neg signal.

Thanx Roy.

Extend the lock time to close the windows, you wont do it with a module, it's all data at the switches. Where have you taken lock and unlock from?

Ive took the lock/unlock from the switch in the centre of the dash.

The A class unlike other mercedes models does not have the feature where you hold the drivers door lock in the locked position to close the windows,neither does it lock/unlock any of the other doors from the drivers door lock.the only place i could find a link to the central locking was at the hazzard/lock switch which was a single wire sending neg pulse to lock and neg pulse to unlock so connceted both lock/unlock wires from alarm via two relays to this.

Im just at a dead end with the windows,what happened to good old 12v electrics

I'm sorry, for some reason I had C class on my mind, to be honest I'm avoiding ANYTHING M/Benz or VAG after 2002!
Having said that, if you can get to the motor wires between the door module and the actual motor you stand half a chance. Otherwise forget it, also your I/start question, how did you by-pass the ignition?

Also just realised you mentioned 2 relays for the locks, 2 diodes would have been more than adequate, especially if you used a 650Mkll or Avant Guard 5.5, they have relay driven locks wires any way. What alarm by the way?

You're looking for 2 wires, they will either be "sitting" to ground (earth) at rest or to 12volts+.
Moving the switch one way, one wire will change state, the other will stay as it is. Move the switch the other way, the reverse happens.
these are the wires you're after.
Having said all this, some points.
I just looked at the wiring diagrammes;
Multifunction module (instrument panel, rear of),
Plug B 1 Blue unlock -.
Plug B 2 Lock blue -. Extend the lock time pulse to close the windows*

Plug A 26, BROWN / white, 27 BROWN / green, 28 BROWN / yellow, these are door and tailgate contacts, diode together.
You're unlikely to find what you want in the door, the only control wires are CAN data.
Also I don't think the 5.1 is up to this, it's too basic * To extend that time pulse you would need a Concept 470 or 650 or add a 528t timer unit.