The supply for the two fans
N11
and
N12
arrives
directly from the battery from the lines of the two maxifuses FAN1
and FAN2 of
B99
: the fans operate when they receive an earth
command.
The relays
J30
,
J31
and
J32
,
specific to the cooling system, receive supply to their coils from
the direct line (EFI) protected by fuse
F5
of the additional
fuse box
B98A
.
They are energized by an earth signal coming
from the engine control 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 42 of connector A - that the
first pressure stage has been reached, control unit M10 sends an
earth signal to 1st speed relay J30 from pin 90 of connector A,
which energizes the coil.
The relay then sends an earth which,
via the additional resistors
O10
and
O12
, operates
both fans
N11
and
N12
which rotate at the first (slow)
speed.
If the engine coolant reaches a higher temperature
level, or the 4 stage pressure switch
K10 (pin 6) signals to
the control unit M10 - pin 81 of connector A - that a higher pressure
level has been reached, then the control unit M10 sends an earth
signal, pin 69 of connector A, to the two 2nd speed fan relays
J31 and J32 which energize the coils.
The two relays then send
an earth directly to the two fans
N11
and
N12
which
rotate at maximum speed.