Switch off seat heater, function

Switching off manually

Press the left front HS [SIH] switch (N72/1s10) or the right front HS [SIH] switch (N72/1s11) until the particular LEDs have gone out.

On vehicles with code (872) Electrically heated left and right rear seats, press the left rear HS [SIH] switch (S51/3s2) or the right rear HS [SIH] switch (S51/4s2) until the particular LEDs have gone out.

It is possible to manually switch off the heated seats HS [SIH] at any time.

Automatic switch-off via timer control

Automatic switch-off is achieved by the

 Passenger-side SAM control unit (N10/11)

(on vehicles as of 1.6.05 without code (872) Electrically heated left and right rear seats and without code (401) Front deluxe seats, incl. seat heating and seat ventilation) or by the

 HS [SIH] and seat ventilation control unit (N25/7)

(on vehicles up to 31.5.05 and on vehicles with code (401) Front deluxe seats, incl. seat heating and seat ventilation or with code (872) Electrically heated left and right rear seats)

via an integrated timer control.

 The operating and function indications of the heated seats (HS) are summarized in the table given below.

The heated seats HS [SIH] are also switched off under the following criteria:

 Switching off after circuit 15R Off

When the ignition is switched off, the heated seats (HS) are also switched off. However, the timer control continues to run for a further 5 minutes as long as circuit 15C is on.

If circuit 15R or circuit 15 is switched on again, the active stage according to the timer control is switched on.

 Switching off in the event of undervoltage

If the values are dropping below the undervoltage threshold, the heated seats HS [SIH] (loads only) are switched off (timer control continues to run). The heated seats cannot be switched on again until a permissible voltage has been present for longer than
20 seconds.

Undervoltage recognition is indicated by the fact that the LEDs in the particular HS [SIH] switch are flashing on and off with a frequency of approx. 1.5 Hz and 50 % brightness.

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 Switching off in the event of overvoltage

When the overvoltage threshold is exceeded, the heated seats HS [SIH] (loads only) are switched off. The timer control continues to run if the heated seats HS [SIH] are switched off due to overvoltage. It is not possible to switch them on again until a permissible voltage is present again.

Additionally, the HS [SIH] and seat ventilation control unit (N25/7) implements the following protective mechanisms:

 Switching off in the event of a hardware defect

If actuation of the heated cushions (R13/1, R13/2 or R13/3 and R13/4) in the driver or front passenger seat and on vehicles with code (872) Electrically heated left and right rear seats of the heated cushions (R13/5, R13/6 and R13/9 or R13/7, R13/8 and R13/10) in the left or right rear seat is recognized without a request being present, the heated seats HS [SIH] are switched off.

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 Temperature-dependent switching off of the heated rear seats HS [SIH]

If the interior temperature increases to more than 40 °C, the heated seats HS [SIH] are switched off.

 If the value for the interior temperature is not available, the value of the outside temperature is used as a backup.