The relay J36 controls the engagement of the first additional heater coilThe relay is supplied from the line of the fuse B38 .The relay J37 controls the engagement of the other two additional heater coils. The supply for relay arrives from the line for maxifuse PTC2, located on the battery, connector B99 .the ignition (INT/A) protected by fuse F49 of the junction unit under the dashboard B2. The climate control unit M70 sends the enabling signal for engaging the first resistance O25A from pin 8 of connector B: this signal excites relay J36. The climate control unit M70 sends a signal for enabling the engagement of the two resistances O25B from pin 7 of connector B: this signal energizes the relay J36.