3315696 - E5020 ENGINE COOLING - Functional description (Automatic transmission)

Functional description

The power supply to fan N11 is controlled by two relays R7 (1. speed) and R6 (2. speed), located in relay control unit B3 . Both relays are supplied with power directly from the battery - junction unit A5 - by a line protected by a special fuse F9 for R7 and F8 for R6 , all located in B3 .

Functional description

These are excited by an earth signal from 4-stage pressure switch K10 and engine management unit M10;

• if the coolant temperature reaches the first temperature stage, or the 4-stage pressure switch K10 pin 3 - indicates to control unit M10 pin 15 of connector E - that the first pressure stage has been reached, control unit M10 sends a signal to 1st speed relay R7 from pin 6 of connector A.
• if the engine coolant reaches a higher temperature level, or the 4-stage pressure switch K10 pin 6 - indicates to control unit M10 pin 17 of connector E - that a higher pressure level has been reached, control unit M10 sends an earth signal to 2nd speed relay R6 from pin 3 of connector D.