Seat Heating, Basic Function - GF91.30-S-9900A
Model All (Light transporter)
Overview
This document contains information on:
- General information
- Function requirements
- Function
- Seat heating control
- Manual switching on and off
- Reduced heating output with multiple activation
- Reduced heating output in ECO drive program
- Actuation by other systems
General information
The seat heating has the task of increasing the temperature of the seat cushion or seat backrest. The seat heating creates a more pleasant climate for vehicle occupants at low temperatures. The seat heating is performed via integrated heating elements in the seats.
Function requirements
- Circuit 15 or circuit 15R ON or vehicle condition = "LIVING"
- Only for front passenger seat heating:
Front passenger seat belt buckle contact (for approx. 15 minutes after change of circuit)
Function
Seat heating control
Control of the seat heater is dependent on the equipment installed:
- If the respective seat is equipped with a seat control unit, it controls the seat heating.
- On seats without a seat control unit, a seat heating control unit or a seat climate control unit is installed.
- With comfort seat heating, the seat control unit is often supported by an additional seat heater control unit.
Manual switching on and off
Depending on the equipment and model involved, the seat climate control switch group is installed in the doors, on the side wall of the respective side of the vehicle or in the armrests. The seat climate control switch group records the control signals via the seat heater button and sends them to the control system.
The heating output can set to 3 different levels. The actuation of the heating elements is performed by means of pulse width modulation (PWM) and thus enables actuation in 3 intensity levels (100%, 65%, 35% power).
The control system sends the stage setting of the seat heating back to the seat climate control switch group. This actuates the LEDs in the seat heating button accordingly.
The heating output of the individual stages is also adjusted depending on the outside temperature. The heating output settings of the respective heating levels can be adjusted via the diagnostic tester.
Depending on the equipment, it is also possible to operate the seat heating in the rear passenger compartment via the vehicle's own tablet PC or the rear touchscreen.
Reduced heating output with multiple activation
If the seat heating is selected again with the same circuit status, the seat heating actuates heating level 3 with only 90% of the heating output.
Reduced heating output in ECO drive program
If the ECO drive program is activated, the seat heating switches to a mode to reduce the operating current. This is done by means of reduced pulse-width modulated signals. The control system multiplies the individual output levels of the pulse width modulated signals by an ECO factor and thus reduces the heating output.
If the ECO drive program is deactivated, the seat heating automatically returns to the normal mode. On vehicles with seat heating Plus, this continues to regulate to the specified temperature, but with reduced PWM values at the output of the actuating control unit.
It is possible to adjust the ECO factors using the diagnostic tester.
Actuation by other systems
For actuation by other systems, the function requirements for circuit 15 or 15R ON are not applicable. With circuit 30t, the other systems can also activate the seat heating.
The seat heating can also be actuated by the following systems:
- Pre-air conditioning
- Revitalization
| Function schematics | |||
| Function schematic for actuating front seat heating | Model 447.8 with code XM0 (Facelift) except code XM7 (MOPF II) except electric vehicles | PE91.30-S-2502-97TRA | |
| Model 447.6 with code XM0 (Facelift) except code XM7 (MOPF II) electric vehicles Model 447.7 with code XM0 (Facelift) except code XM7 (MOPF II) electric vehicles | PE91.30-S-2502-97TRB | ||
| Model 447.8 except code XM7 (MOPF II) electric vehicle | PE91.30-S-2502-97TRC | ||
| Model 447.6 except code XM7 (MOPF II) electric vehicles Model 447.7 except code XM7 (MOPF II) electric vehicles | PE91.30-S-2502-97TRD | ||
| Model 447 with code XM7 (MOPF II) | PE91.30-S-2502-97A | ||
| Function schematic for actuating rear seat heating | Model 447.8 with code XM0 (Facelift) except electric vehicles | PE91.30-S-2503-97TRA | |
| Model 447.8 electric vehicles | PE91.30-S-2503-97TRB | ||
| Model 447 with code H05 (Climatised rear seats) with code XM7 (MOPF II) Model 447 with code H07 (Climatised rear seats, 2nd row) with code XM7 (MOPF II) | PE91.30-S-2503-97A | ||
| Model 447 with code U90 (Left luxury seat of 1st seat row) with code XM7 (MOPF II) Model 447 with code U91 (Right luxury seat of 1st seat row) with code XM7 (MOPF II) | PE91.30-S-2503-97B | ||
| Further basic functions | |||
| Tablet cradle electric controller unit, basic function | GF54.21-S-2007A | ||
| Seat control unit, basic function | GF91.29-S-9890A | ||
| Seat climate control timer-controlled shutoff, basic function | GF91.30-S-1000A | ||
| Seat climate control automatic shutoff, basic function | GF91.30-S-1001A | ||
| Seat climate control unit, basic function | GF91.30-S-9891A | ||
| Component descriptions | |||
| Seat heating heater pad/heat mat, component description | Model 420 | GF91.30-S-3211VRA | |
| Heated seats/seat ventilation control unit, component description | Model 447 with code H15 (Seat heater for front passenger) with code H16 (Seat heater for driver) with code XM7 (MOPF II) |
GF91.30-S-5209A | |
| Model 447 with code H05 (Climatised rear seats) with code XM7 (MOPF II) Model 447 with code H07 (Climatised rear seats, 2nd row) with code XM7 (MOPF II) |
GF91.30-S-5209B |