The supply for the fan
N11
arrives
directly from the battery from the line for the maxifuse
B8
:
the fan therefore operates when it receives an earth command.
The relays
J30
and
J31
have
coils supplied by the line controlled by the ignition (15/54) protected
by fuse
B25
.
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 35 of connector A)
that the first pressure stage has been reached, control unit
M10
sends an earth signal (from pin 40 of connector A) to the fan
J30
1st speed relay 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 1) signals
to the control unit
M10
(pin 21 of connector A) that a second
pressure stage has been reached, then the control unit
M10
sends an earth signal (from pin 14 of connector A) 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.