Rear Heated Seats

REAR HEATED SEATS

DESCRIPTION

General
Operation of the rear electric seats is continued by the two seat heat switches located on the rear face of the center console. Pressing the relevant seat heat switch once will heat the seat to a temperature of 44 °C (111 °F ) and illuminate two LED'S on the switch face. Pressing the seat heat switch a second time will lower the temperature to 39 °C (102 °F ) and illuminate one LED on the switch face. Pressing the switch a third time switches off the seat heat function and extinguishes the remaining LED.

OPERATION

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fusible link 1 and fuse 53 of the passenger compartment fuse box (C0632) on an R wire. Fusible link 1 (C0588) is connected to fuse 11 of the rear fuse box (C2024) by an R wire. Fuse 11 provides a constant battery feed to the rear heated seat relay, which is also located in the rear fuse box.

Fuse 53 of the passenger compartment fuse box (C0583) is connected to the ignition switch(C0099) by a G wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028 on V8 vehicles) to fuse 2 of the passenger compartment fuse box (C0585) on a G wire. Fuse 2 (C0587) provides an ignition feed to the rear heated seat relay coil (C2022) on a GY wire. The relay coil (C2021) is earthed on an N wire. The energised rear heated seat relay (C2021) provides a feed to the LH rear seat heat switch (C1401) on a GW wire, and the RH rear seat heat switch (C1403) on a GN wire. Both switches are earthed on NB wires.

RH Rear Seat
When the RH rear seat heat switch (C1401) is pressed it provides a feed to the cushion heater matrix (C2085) on a WY wire. The heater matrix (C2085) is earthed on an N wire. The seat heat switch (C1401) monitors the temperature of the cushion heater matrix (C2085) by providing a feed to a Negative Temperature Coefficient (NTC) sensor on a YN wire. The sensor is earthed 011 an N wire. By calculating the resistance of the NTC sensor, the switch can determine the temperature of the seat and regulate the supply voltage to the RH rear heater matrix accordingly.

LH Rear Seat
When the LH rear seat heat switch (C1403) is pressed it provides a feed to the cushion heater matrix (C2084) on a BY wire. The heater matrix (C2084) is earthed on an N wire. The seat heat switch (C1403) monitors the temperature of the cushion heater matrix (C2084) by providing a feed to a Negative Temperature Coefficient (NTC) sensor on a WN wire. The sensor is earthed on an N wire. By calculating the resistance of the NTC sensor, the switch can determine the temperature of the seat and regulate the supply voltage to the LH rear heater matrix accordingly.