Seat heating

The cushion surfaces and backrests are heated with the seat heating system.

Function

The seat heating can be switched on as of terminal 15 by pressing the button. The LED integrated in the switch lights to act as a function indicator.

The seat heating is switched off by pressing the button once again or switching off the ignition.

The seats are heated by means of four heating elements incorporated in the upholstery.

• Cushion surface
  
• Seat moulding and thigh support
  
• Centre section of backrest
  
• Backrest moulding
  

The electronic circuitry integrated in the switch controls and monitors the seat heating function.

The heating temperature can be adjusted by means of a potentiometer within the range from 20 ^o C to 42 ^o C. The temperature is measured by a temperature sensor in the seat upholstery and passed on to the electronics integrated in the switch.

The electronic circuitry controls the heating function such that the set temperature is reached in the fastest possible time. The heating capacity is then reduced.

Note

Current supply to the heat conductor of the seat heating electronics is interrupted if the vehicle battery voltage drops below 11.8 volts. The function LED installed in the switch however remains on. Current supply to the heat conductor is resumed when the battery voltage again reaches 11.8 volts.

Fault monitoring

The seat heating electronics monitors the temperature sensor and the heating elements for faults.

If a break or short occurs at the temperature sensor, the seat heating is switched off in order to prevent overheating.

Fault indicator

If a fault is recognized, the function LED installed in the switch flashes for 12 seconds when the fault occurs, or, if the fault is already present, when the seat heating is switched on.

Flash code

A flash code shows what faults the electronic circuitry has currently detected.

Flash code output is started by following procedure:

• Switch off ignition
  
• Press and hold the button for seat heating
  
• Switch on ignition (terminal 15) with button depressed
  
• Release the button and press it again briefly
  

The following faults can be indicated: