223002796 - E5020 ENGINE COOLING - FUNCTIONAL DESCRIPTION (Climate control system, MY 2005)

The power supply to fans N11 and N12 reaches the battery directly via relays R6 and R7 contained in engine compartment junction unit B01 from a line entering pin 1 connector A of the control unit.The power supply to the relays is protected by fuses F7 for relay R7 and F6 for relay R6.These are excited by two different earth signals from engine control unit M10.Engine temperature sensor K36 measures the cdoolant temperature. If temperature values are high, control unit M10 sends an earth signal from pin 90 connector A to relay R6 (which controls the first fan speed), which excites the coil. Relay R6 then sends a power supply to operate fans N11 and N12 positioned in series by remote control switch J39, at the first speed (slow).High climate control system pressure, detected by pressure switch at 4 or the reaching of a high coolant temperature, determines activation of the second fan speed.    See E6021 COMPRESSOR ENGAGEMENTIn this case, control unit M10 sends an earth signal from pin 69 connector A to relay R7 and simultaneously to remote control switch J39, which arranges the power supply of fans N11 and N12 in parallel to control the second rotation speed of both fans.