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 for maxifuse UGD of
B5
protected by
fuse
B35.
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 52 of connector A - that the
first pressure stage has been reached, control unit M10 sends a
signal to 1st speed relay R7 from pin 20 of connector A. 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 51 of connector A) that a high
pressure stage has been reached, then the control unit
M10
sends an earth signal (from pin 19 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.