Windows: Description and Operation

Power Windows (FH/ZKE):

General Block Diagram:

Functional Description:

General:

The power windows (FH) are controlled by the general module (GM) of the central body electronics (ZKE). The power window relays are in the relay module (RM). The working circuits are provided by the external fuse relay.

Operation:

The power windows can be operated by the front control switch (center console) or the rear control switch (in the doors). The switches connect the general module to ground.

It is possible to operate the power windows (and the sunroof) for as long as the switch lights are on. The lights switch on when the ignition is switched on (terminal 15) and, depending upon the country-specific coding, go out when the ignition is switched off or after ignition OFF and opening/closing the driver's or passenger's door.

Child Lock:

The rear switches are made inoperable by pressing the safety switch in the front operating unit. The switch lights go out.

Operating Principle:

The power window system and the sunroof are switched by a total of seven relays. The circuit is designed in such a way that several relays are driven simultaneously for the direction "close window" or "open/lower sunroof". All five motor drives are connected to one common relay only for the direction "open window" or "close/raise sunroof".

Automatic Strike Feature:

General Module up to Model Year '91:

Only effective at the driver's door.

The window is completely opened or closed automatically by briefly striking the switch for the driver's power window. Operation of any other power window switch interrupts this opening/closing sequence immediately.

General Module as of Model Year '92:

The automatic strike function in the direction "open window" is effective at all doors. The opening procedure is interrupted when the corresponding switch is pressed once again.

The automatic strike feature at the driver's door is also effective in the "close" direction.

Central Closing:

The windows and the sunroof can be closed with the door locks. For this purpose, the key must be held in the lock and arrest position for approx. 2 seconds. The power window motor drives are activated in the sequence: Passenger's side - driver's side - sunroof. The general module detects when a window is completely closed by way of end position sensors. The sensors switch ground for as long as the window is open.

Country-Specific Variants:

In the ECE/US models, country-specific coding is accomplished with the general module via D13 (yellow connector, Pin 13) which, in the case of the US version, is connected to ground. The Finland and Australia models have their own software versions (*D* Control unit identification).

ECE version: Windows can still be operated after switching off the ignition. Operation is deactivated after opening or closing the driver's or passenger's door.

US version: Operation is deactivated after switching off the ignition and opening the driver's or passenger's door.

Scandinavia: Switch-off conditions as ECE model, but no automatic strike function for driver's window and sunroof.

Australia: Windows and sunroof can still be operated after switching off the ignition. Operation is deactivated after opening the driver's door (as ECE). Automatic strike function only at driver's door.