E63/E64 Centre Console Switch Cluster
Installation location
The center console switch cluster (SZM) is installed in the center console.
| Item | Description | Item | Description |
|---|---|---|---|
| 1 | Integrated automatic heating and air-conditioning system | 2 | Audio CD drive |
| 3 | DVD drive | 4 | Centre-console switch cluster (SZM) |
Construction
The center console switch cluster (SZM) is configured corresponding to the optional equipment installed in the vehicle. Push-buttons and LEDs are installed corresponding to the selected optional equipment. The electronic circuits are also adapted to requirements. The DSC button (dynamic stability control) is integrated in the center console switch cluster as standard.
The following table illustrates the combination options of the SZM on the E63 and E64.
| DSC (standard) |
PDC (option 508) | Convertible top | Seat heating left and right (option 494) |
|
| E63 | X | |||
| X | X | |||
| X | X | |||
| X | X | X | ||
| E64 | X | X | ||
| X | X | X | ||
| X | X | X | ||
| X | X | X | X | |
| 1 LED | 1 LED | 2x3 LEDs |
The operating switches or push-buttons are arranged as follows:
| Item | Description | Item | Description |
|---|---|---|---|
| 1 | Housing of center console switch cluster (SZM) | 2 | LED for seat heating, right |
| 3 | Seat heating switch, right | 4 | PDC switch (park distance control button) |
| 5 | LED indicator for PDC | 6 | OPEN button for convertible top |
| 7 | CLOSE button for convertible top | 8 | LED indicator for convertible top |
| 9 | DSC button | 10 | Seat heating switch, left |
| 11 | LED seat heating, left | 12 | Plug connection, 13-pin |
| 13 | Plug connection, 6-pin | 14 | Plug connection, 8-pin |
Pin Assignments, 13-Pin Plug Connection
| Pin | Type | Description |
|---|---|---|
| 1 | V | Terminal 30, power supply |
| 2 | A | Seat heating, left |
| 3 | A | Seat heating, right |
| 4 | E | Signal from Hall sensor 1 for steering column UP/DOWN adjustment |
| 5 | M | Ground to Hall sensor 1 for steering column UP/DOWN adjustment |
| 6 | E | Signal from Hall sensor 2 for steering column IN/OUT adjustment |
| 7 | M | Ground from Hall sensor 2 for steering column IN/OUT adjustment |
| 8 | E | Signal from switch for dynamic driving control (FDC) |
| 9 | A | Signal for dynamic driving control (FDC) |
| 10 | M | Negative line to switch for dynamic driving control (FDC) |
| 11 | E/A | CAN-bus high |
| 12 | E/A | CAN-bus low |
| 13 | E/A | Body bus |
| A = Output | ||
| E = Input | ||
| E/A = Input and output | ||
| M = Earth | ||
| V = Power supply | ||
| For current specifications regarding pin assignment, please refer to BMW diagnosis system | ||
Pin assignments, 6-pin plug connection
| Pin | Type | Description |
|---|---|---|
| 1 | V | Terminal 30g |
| 2 | M | Terminal 31, ground |
| 3 | A | DSC data |
| 4 | E | Terminal 58g, locator lighting |
| 5 | E | Temperature sensor, left |
| 6 | E | Temperature sensor, right |
| A = Output | ||
| E = Input | ||
| E/A = Input and output | ||
| M = Earth | ||
| V = Power supply | ||
| For current specifications regarding pin assignment, please refer to BMW diagnosis system | ||
Pin assignments, 8-pin plug connection
| Pin | Type | Description |
|---|---|---|
| 1 | M | Earth |
| 2 | V | Terminal 30g |
| 3 | A | Power supply for drive unit for steering column IN and UP adjustment |
| 4 | A | Power supply for drive unit for steering column OUT and DOWN adjustment |
| 5 | A | Power supply for changeover of steering column UP/DOWN adjustment |
| 6 | A | Power supply for changeover of steering column IN/OUT adjustment |
| 7 | A | Power supply for convertible top OPEN (E64 only) |
| 8 | A | Power supply for convertible top CLOSE (E64 only) |
| A = Output | ||
| E = Input | ||
| E/A = Input and output | ||
| M = Earth | ||
| V = Power supply | ||
| For current specifications regarding pin assignment, please refer to BMW diagnosis system | ||
How it works
The center console switch cluster (SZM) serves as the data interface (gateway) between the body bus (K-bus) for the seats and the body controller area network (K-CAN) of the E63/E64. The K-bus is a single-wire connection. The K-CAN is a two-wire connection. The SZM converts the signals from the K-bus and transmits them on the K-CAN. The SZM co-ordinates the control and memory functions. Communication takes place via the K-CAN, byteflight or by means of direct wiring.
The center console switch cluster controls the following functions:
- Seat heating for driver's seat and passenger's seat
Both seat heating systems are actuated directly by the center console switch cluster (SZM). The SZM provides the power supply via a direct line to the seat heating mats. The temperature sensors in the seat upholstery measure the current temperature of the seats. After reaching the set temperature, a pulse-width modulated signal ensures the heating temperature is kept constant. The center console switch cluster (SZM) controls the clock cycle of the pulse-width modulated signal corresponding to the selected heating stage. The heating output management system reduces the heating output in the event of a drop in the system voltage.
- Steering column adjustment
The switch for steering column adjustment is integrated in the steering column switch cluster (SZL). The center console switch cluster (SZM) controls the steering column adjustment via a direct line.
- Seat adjustment through key memory
The positions of the driver's seat are stored in the driver's seat module (SMFA). The signals from the key memory are sent via the K-CAN to the center console switch cluster (SZM). The SZM passes on the signals via the K-bus to the driver's seat module (SMFA). The SMFA controls the corresponding drive units and positions. The SZM simulates encoding of the seat modules for certain functions. For instance, the customer selects the moment of seat adjustment via the CID. In the E46, this was possible only via the car memory.
- Park Distance Control
The signals from the PDS switch (park distance control) are routed via the K-CAN to the corresponding control unit.
- Convertible top operation
The convertible top in the E64 is operated by means of the "convertible top OPEN" and "convertible top CLOSE" buttons. The SZM passes on the signals via a direct connection to the convertible top module (CVM). A feedback signal is sent via the K-CAN. The LED indicator in the SZM then indicates the status of the convertible top.