The supply for fan
N11
arrives directly
from the battery from the line for the maxifuse FAN 1 of
B99
:
the fan therefore works when it receives an earth command.
The specific relays
J30
and
J31
for
the cooling system have coils supplied by 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 engine coolant temperature reaches
the first temperature stage, or the 4 stage pressure switch
K10
(pin
3) signals to the control unit
M10
that the first pressure
stage has been reached, then the control unit
M10
sends an
earth signal to the 1st speed fan relay
J30
which energizes
the coil. The relay then sends an earth signal which, via the additional
resistance
O10
, operates the fan
N11
which rotates
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
that a higher pressure stage has
been reached, then the control unit
M10
sends an earth signal
to the 2nd speed fan relay
J31
which energizes the coil.
The relay then sends an earth signal directly to the fan
N11
which
rotates at the maximum speed.