The relays
J30, J31 and J32 located next
to the engine compartment junction unit manage the engagement of
the two fans N11 and N12 at two speeds: their coils are supplied
by the line for fuse F6 of the engine compartment junction unit
B1A.
The relays are energized by a control signal
- earth - coming from the engine control unit
M10.
If the engine coolant reaches a first temperature
level, or the 4-stage pressure switch
K10 indicates to the control
unit M10 - pin 9 of connector A - that a first pressure level has been
reached, the control unit M10 sends a signal - from pin 50 of connector
A - to the fan 1st speed relay J30, which then sends the supply
to the fan N11 via the additional resistor O10 and to the fan N12
via the additional resistor 012: the two fans thus turns at the
first speed (slow).
If the coolant reaches a higher temperature
level, or the 4-stage pressure switch
K10 indicates to the control
unit M10 - pin 41 of connector A - that a higher pressure has been reached,
the control unit M10 sends a signal - from pin 62 of connector A
- to the two 2nd speed relays J31 and J32, which send the supply
directly to the fan N11 and to the fan N12: the two fans then turn
at the maximum speed.