Button for operation

The center console switch cluster is equipped with 2 buttons ('open convertible top' and 'close convertible top') for convertible top operation. The center console switch cluster (SZM) is connected to the operating unit of the climate control (= control module).

Fig 1: Identifying Close/Open Convertible Top Button

Courtesy of BMW OF NORTH AMERICA, INC.

There is a red and green function LED above the two buttons. The control LEDs are activated by the convertible top module (CVM) via the K-CAN.

The green LED lights up during convertible top movement. The red LED starts to flash if the convertible top or convertible top cover is not in a safe end position when the button is released.

The red LED flashing does not indicate a fault. The flashing LED is intended to indicate that in the vehicle must not be driven in this status.

The red LED lights up if the convertible top is opened by pressing a button and there is a block condition (e.g. convertible top compartment floor not down).

The red LED also lights up on closing the convertible top if there is a block condition (e.g. luggage compartment lid or temperature).

The two control buttons are designed with 2 double contacts (make contact to ground). A direct line leads to the CVM and reports a general operation request. The second line reports the direction to the control module for the climate control (IHR, IHKR, IHKA). Subsequently, the signal is sent via K-CAN to the CVM.

This means that an operation request is executed with a delay. If the button is released during the movement, the convertible top movement or side window movement stops immediately.