Comfort displays, function - GF54.30-P-3043RC

General function requirements  Instrument cluster (A1) activated

General convenience display function sequence  The convenience displays permit a rapid overview of information which is not required for operating the vehicle. The convenience display comprises the following subfunctions: Outside temperature indicator function sequence, Time display function sequence, Instrument cluster illumination function sequence.

Outside temperature indicator function sequence  The outside temperature is recorded by the outside temperature indicator temperature sensor (B14), read in by the driver-side SAM control unit with fuse and relay module (N10/1) and forwarded to the instrument cluster via interior CAN. In order to determine a correct value of outside temperature, the following parameters must also be taken into account: Vehicle speed (distortion of value by the airstream) - Coolant temperature (distortion of the value by radiant heat)

The coolant temperature values have an influence on the outside temperature indicator as follows:

Coolant temperature T < 60 °C: The current outside temperature value is always displayed.

Coolant temperature T > 60 °C and circuit 61 On: At a speed of v < 20 km/h (12 mph) the display only changes if the measured outside temperature value decreases. At speeds between v = 20 km/h and v = 45 km/h, rising outside temperatures are displayed after a delay period of t = 3 min. At speeds > 45 km/h, rising outside temperatures are displayed after a delay period of t = 90 s. If the vehicle speed signal is faulty, increasing temperatures are displayed every t = 10 min in a buffered manner.

Coolant temperature T > 60 °C and circuit 61 Off: A delay period (max.. t = 1 h) prevents that an apparent increased outside temperature is displayed due to heat dissipated from the engine. A rise in display value is not permitted during this delay period.

With circuit 15 OFF, the last measured temperature value is stored and then displayed when circuit 15 is switched on. If the measured outside temperature has since fallen below the stored value, the current measured temperature is displayed.

The outside temperature is shown in the lower multifunction display (A1p15). The display range is between -40 °C and +85 °C

If the instrument cluster receives an implausible or no coolant temperature, then the display of outside temperature is controlled as if the coolant temperature were T > 60 °C.

Time display function sequence  The analog time is displayed via the electronic clock (A1p6). On vehicles without navigation the time can be adjusted manually via the left multifunction steering wheel button group (S110) and the right multifunction steering wheel button group (S111). The signals are read in by the steering column tube module (N80) and transmitted to the instrument cluster via the interior CAN. On vehicles with navigation, the time always synchronizes with the installed audio components.

Instrument cluster illumination function sequence  The illumination is switched on automatically when the instrument cluster is activated. If the instrument cluster is activated via the opening of the driver's door, the illumination switches off again after t = 30 s. If an active warning is displayed then the run-on time extends to t = 2 min. The brightness is automatically adjusted to suit the lighting conditions in the interior compartment by a phototransistor integrated in the instrument cluster. The brightness can also be changed individually by actuating the instrument illumination variable resistor (A1r1) if the exterior lights are switched on.