Heated seats/seat ventilation control unit, component description

P91.30-2240-04

N25/7 HS [SIH], seat ventilation and steering wheel heater control unit

Location

The HS [SIH], seat ventilation and steering wheel heater control unit is located on the crossmember under the left seat in the second seat row.

Task

The HS [SIH], seat ventilation and steering wheel heater control unit is connected to the Controller Area Network bus Class B (interior) (CAN-B) for exchanging data.

The following functions are actuated over the HS [SIH], seat ventilation and steering wheel heater control unit, in accordance with the requests received via CAN-B:

 The heated seats (SIH) for left and right rear seats (each with timer control)
(for electrically heated left and right rear seats, code 872)

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Voltage supply

The following components receive their voltage supply straight from the HS [SIH], seat ventilation and steering wheel heater control unit:

 Left 2nd row seat heated cushion (R13/5)

 Left 2nd row backrest heated cushion (R13/6)

 Right 2nd row seat heated cushion (R13/7)

 Right 2nd row backrest heated cushion (R13/8)

Switching internal relay

 Relay for 2nd seat row heated seats

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Discrete inputs

 Terminal 30

 Circuit 31

Discrete outputs

 Voltage supply for rear heated seats

 2nd seat row heated seat cushion

 2nd seat row backrest heated cushion

Time control

A timer control is located in the HS [SIH], seat ventilation and steering wheel heater control unit for the heated seats.

Automatic initial startup of heated seats in stage 3 for 5 min when switch actuated. After this, there is a switching over to stage 2 for 10 min, which in turn is deactivated by switching to stage 1. Stage 1 has a runtime of 20 min and then switches off automatically.