The services relay T21, located in the boot junction unit B045, supplies:- via the battery line protected by fuse F57, the driver''s front seat heating control unit M170 - pin 5 and the switch for the driver''s heated seat I065 - pin 2;- via the line protected by fuse F67, the passenger front seat heating control unit M110 - pin 5 and the switch for the passenger side heated seat I066 - pin 2;Power pin 30 for relay T21 of the boot junction unit B045, receives a power supply from the direct battery line via the junction unit under the dashboard B002 pin A connector B, pin B connector C protected by fise F1 of junction unit B001.The coil for relay T21 is supplied by relay T12 of the junction unit under the dashboard B002; relay T12 is activated by the supply line (INT) when the ignition key is in the ON position.The LEDs inside switches I066 and I065 with a backlighting function, receive a power supply at pin 1 via the line (INT) controlled by the ignition protected by fuse F49 of the junction unit under the dashboard B002.For the driver''s seat.The heater pad with the driver''s front temperature sensor O046 and the heater pad for the driver''s front backrest O048, connected in series, are supplied at pins 3 and 2 of switch I065 - pin 3.Pin 7 of the driver''s front seat heating control unit M170 receives the signal from the temperature sensor in the heater pad in the seat cushion whilst pin 6 receives a voltage signal for controlling the system.For the passenger seat.The heater pad with the passenger front temperature sensor O047 and the heater pad for the passenger front backrest O049, connected in series, are supplied at pins 3 and 2 of switch I066 - pin 3.Pin 7 of the passenger front seat heating control unit M110 receives the signal from the temperature sensor in the heater pad in the seat cushion whilst pin 6 receives a voltage signal for controlling the system.