GF46.11-P-0001TX Steering Wheel Heater (LRH), Function

GF46.11-P-0001TX Steering wheel heater (LRH), function
- with CODE (443) Steering wheel heater

15.03.07 The document has been updated to this date and will no longer be subject to revision.

Component Identification:

The rim of the steering wheel can be heated to render manual contact both more comfortable and more secure in the cold. User-control is with the steering wheel heater switch, while system control is assumed by the HS [SIH] and seat ventilation control unit.

Function requirements
^ Circuit 15R or circuit 15 ON
^ Interior temperature < 30 degrees C

Switching on
^ Turn the steering wheel heater switch up.
^ Signals are monitored by the steering column module and transferred through CAN-B to the HS [SIH] and seat ventilation control unit.
^ The heater elements in the steering wheel rim receive electrical power from the HS [SIH] and seat ventilation control unit and the steering wheel heater electronics. The heater element temperature sensor registers the temperature of the steering wheel rim. The steering wheel heater electronics monitor these data for use in closed-loop control (temperature target c. 35 degrees C).

Function indicator
A display within the steering wheel heater switch indicates that the steering wheel heater is on (LRH).

Manual deactivation
^ Turn the steering wheel heater switch down.
^ Signals are monitored by the steering column module and transferred through CAN-B to the HS [SIH] and seat ventilation control unit.
^ The HS [SIH] and seat ventilation control unit deactivates the steering wheel heater (LRH). The display goes out.

Automatic deactivation
^ Once the maximum heating period elapses (continuous heater operation for 15 minutes) the system is deactivated by the HS [SIH] and seat ventilation control unit. The display goes out.
^ The HS [SIH] and seat ventilation control unit also responds to interior temperatures in excess of 30 degrees C by deactivating the system.
The display remains on.

Temperatures within the passenger compartment are relayed from the AAC [KLA] control and operating unit via CAN-B.

^ Term. 15R is switched off.

The timer control continues for an additional 5 minutes if Terminal 15C is on. If Terminal 15R is switched on again during this period the steering wheel heater will also be reactivated.

^ The steering wheel heater is deactivated while the engine is starting. The display remains active.
^ The steering wheel heater is deactivated in response to low on-board voltage. The display starts to flash at 1.5 Hz and 50% brightness. The system can be reactivated 15 seconds after the on-board system's voltage returns to a level above the deactivation threshold.
^ The steering wheel heater is deactivated in response to high on-board voltage. The display starts to flash at 1.5 Hz and 50% brightness. Once the system voltage returns to a level below the overvoltage threshold the heater is reactivated.

Switching off in case of hardware defect
The HS [SIH] and seat ventilation control unit and the steering wheel heater's electronic control circuitry respond to recognized defects in the steering wheel heater (LRH) with deactivation of the entire unit, accompanied by entry of an error code in the malfunction log.