The relay J36 controls the engagement circuit for the first additional heater coil O25A; the power supply for the relay arrives from the line for fuse F74 of the additional fuse box B98.The relay J37 controls the engagement circuit for the other additional heater coil O25B; the power supply for the relay arrives from the line for fuse F76 of the additional fuse box B98.The coils for relays J36 and J37 receive an ignition-controlled supply (INT) from the line for fuse F51 of the junction unit under the dashboard B2. This power supply is interrupted in the casing of overheating by safety switch I95.The coil for relay J36 is energized by a signal for the engagement of the first resistance for O25A - from pin 5 of supplementary heater control unit M75.The coil for relay J37 is energized by a signal for the engagement of the first resistance for O25B - from pin 8 of supplementary heater control unit M75.The control unit M75 receives a power supply, at pin 4, from the ignition-controlled line (INT) for fuse F51 of the junction unit under the dashboard B2. This power supply is interrupted in the casing of overheating by safety switch I95.Pin 2 of M75 is earthed.Supplementary heater control unit M75 is connected – from pins 3 and 6 - via the CAN line, to Body Computer M1 and to the other network nodes. See E1050 CAN CONNECTION LINES The Body Computer M1 receives a direct supply from the battery via the line protected by maxifuse B99 at pin 18 of connector F of the interface with the junction unit under the dashboard B2; the ignition-controlled supply (INT) reaches pin 9 of connector F of the interface with the junction unit B2.When the heater is on, fan N85 is controlled from pin 9 of M75.Fan N85 is supplied from a line protected by fuse F8 and relay T8 of engine compartment junction unit B1: it is an ignition-controlled line (INT/A) for fuse F31 of the junction unit under the dashboard B2.