Switch off seat heater, function

Function requirements

 "Circuit_15R_ON"

 Front seat heater (SIH) is activated

 No overvoltage or undervoltage

The upper control panel (UCP) control unit (N72/1) reads in the signals from the left seat heater button (N72/1s2) or the right seat heater button (N72/1s10) and actuates the power output depending on the selected heating level, i.e. current rating that heats the heating wire, to the respective heating elements:

 Left front seat cushion heater pad (R13/1)

 Left front backrest heated cushion (R13/2)

 Right front seat cushion heater pad (R13/3)

 Right front backrest heated cushion (R13/4)

Switch off seat heater as from facelift 2013

Switching off manually

The front seat heater is manually switched off after a 4th press of the left seat heater button or the right seat heater button.

Automatic switch off

Function requirements

 Heating level 3 activated, 100 % heat output, 3 LEDs light up

or

 Heating level 2 activated, 70 % heat output, 2 LEDs light up

or

 Heating level 1 activated, 40 % heat output, one LED lights up

Timer control is provided by the upper control panel (UCP) control unit. Heating level 3 is active for t = 8 min. Then the system automatically switches to heating level 2. Heating level 2 is active for t = 10 min. Then the system automatically switches to heating level 1. Heating level 1 is active for t = 20 min. Then the seat heater is automatically switched off.

 The time settings of the three heating levels can be set using the diagnostic tester.

Switch off after "Circuit 15R OFF"

At "Circuit 15R OFF" and "Circuit 15C ON", the timer control runs on for another t = 5 minutes. If circuit 15R is switched on again, the front seat heater is switched on again.

Switch off with undervoltage or overvoltage

At undervoltage or overvoltage, the upper control panel (UCP) control unit switches off the front seat heater. The LEDs of the left seat heater button or the right seat heater button remain initially switched on. If the on-board electrical system voltage is stabilized again within a period of t = 3 min, the front seat heater starts again automatically. If the shutoff lasts for longer than t = 3 min however, then the LEDs of the left seat heater button or the right seat heater button are switched off. If the front seat heater is requested again despite being switched off, the LEDs of the left seat heater button or the right seat heater button light up for t = 1.5 s before then going out again.

Switching off in the event of a hardware defect

If actuation of the heater pads without a pending request from the left seat heater button or the right seat heater button is detected, the upper control panel (UCP) control unit switches off the front seat heater.

Switch off seat heater up to facelift 2013

Switching off manually

When the left seat heater button or the right seat heater is pressed upwards again, heating level 1 on the front seat heater is deactivated. This is indicated by the activated LED of the left seat heater button or the right seat heater button going out.

When the left seat heater button or the right seat heater is pressed downwards again, heating level 2 on the front seat heater is deactivated. This is indicated by the 2 LEDs of the left seat heater button or the right seat heater button going out.

 Heating level 2 on the front seat heater is automatically switched after t = 5 min to heating level 1.

Automatic switch-off of the front seat heater after an interrupted start operation

Function requirements

 "Circuit 15R OFF"

 "Circuit_15C_ON"

The upper control panel (UCP) control unit interrupts the power output at the following heating elements:

 Left front seat sitting surface heated cushion

 Left front backrest heated cushion

 Right front seat sitting surface heated cushion

 Right front backrest heated cushion

This is indicated by the activated LED of the left seat heater button or the right seat heater button going out.

The time interval for heating level 2 of the front seat heater is stopped. If within a period of t = 30 s the "Circuit 15R ON" status is activated again, then the front seat heater is activated again in the previously active heating level without the left seat heater button or the right seat heater button being actuated again.

If the "Circuit 15C OFF" status is activated, then the front seat heater is deactivated.

Automatic switch-off of the front seat heater during the start operation

Function requirement

 "Circuit 15X OFF"

The upper control panel (UCP) control unit interrupts the power output at the following heating elements:

 Left front seat sitting surface heated cushion

 Left front backrest heated cushion

 Right front seat sitting surface heated cushion

 Right front backrest heated cushion

The left seat heater button or the right seat heater button LEDs remain lit.

If the upper control panel (UCP) control unit detects the "Circuit 15X ON" status again, then the front seat heater is activated again with a 2 s delay in the previously activated heating level.

Automatic switch-off of the front seat heater during irregular idling

Function requirements

 "Circuit 61 ON"

 "Idling irregular" signal

The upper control panel (UCP) control unit interrupts the power output at the following heating elements:

 Left front seat sitting surface heated cushion

 Left front backrest heated cushion

 Right front seat sitting surface heated cushion

 Right front backrest heated cushion

The left seat heater button or the right seat heater button LEDs remain lit.

If the upper control panel (UCP) control unit detects the "Stable idling" signal, then the front seat heater is activated again in the previously active heating level.

Automatic switch-off at battery voltage U  11 V

Function requirements

 "Circuit_15R_ON"

 Front seat heater activated

 Battery voltage U  11 V present for longer than t = 3 s

The upper control panel (UCP) control unit interrupts the power output at the following heating elements:

 Left front seat sitting surface heated cushion

 Left front backrest heated cushion

 Right front seat sitting surface heated cushion

 Right front backrest heated cushion

This is indicated by the LED of the left seat heater button or the right seat heater button flashing on and off.

 If the battery voltage U  11 V is present for longer than t = 30 s, then a fault is stored in the upper control panel (UCP) control unit.

 If a battery voltage U  15 V is present for longer than t = 3 s, then the front seat heater is immediately deactivated. The left seat heater button or the right seat heater button LEDs go out.