The power supply to both fans
N11 and
N12 (always operated in parallel) is controlled by three relays
J30 (1st speed) external and T6 and T7 (2nd speed), located inside
junction unit B1.
Relays
J30, T6 and T7 are supplied by
the lines protected by fuses F6 and F7 of engine compartment junction
unit B1.
Relay
J30 has a coil supplied by the
line for fuse F18 of junction unit B1
The relays are energized by a control signal
- earth - coming from the engine control unit
M10, pins 19 and
20 of connector A.
If the engine coolant reaches a first temperature
level or sensor
K10 signals to control unit M10 pin 52 of connector
A that a certain pressure level has been reached, then control unit M10
sends a signal from pin 20 of connector A which energizes the fan
1st speed relay J30 which then sends a supply to the two fans N11
and N12 via the additional resistances O10 and O12 so that the fans
turn at the first speed (slow).
If the coolant reaches a higher temperature
level, or the fan linear sensor
K10 indicates to the control
unit M10 pin 51 of connector A that a higher pressure has been reached,
the control unit M10 sends a signal - from pin 19 of connector A
- to the fan 2nd speed relays T5 and T7 of B1, which directly send
the supply to the fans N11 and N12: the fan then turns at the maximum
speed.