PREVOST X3-45 Multiplex, Maintenance Manual

Page: 166 / 1422

Section 06: ELECTRICAL
PA1562
30
Problem/Symptom Probable Causes Actions
Active” indicates a power problem on
the module. (A CAN network problem
would show the same message but
doesn't produce this symptom).
2. Check / reset circuit breaker CB5
3. Check / replace fuse F67 , F68
4. Probe gray connector on module to
see if it is powered.
Sound system not
functioning Circuit breaker CB4 or CB11
was manually tripped and not
reset Check / reset circuit breaker CB4 or CB11
Fire alarm telltale light
and audible alarm always
ON and there is no fire or
high temperature in the
engine compartment Short-circuited fire sensor or
defective sensor Prior to start the vehicle, cycle the ignition
key to the ON position, OFF position and
then ON position again and then start the
vehicle. This will deactivate the fire alarm
function. This has to be repeated each
time the vehicle is re-started
The vehicle is parked and
the electrical horn is acti-
vated to indicate a fire in
the engine compartment
but there is no fire Short-circuited fire sensor or
defective sensor Cycle the ignition key between the ON
and OFF position twice within 3 seconds.
This will deactivate the fire alarm function.
This has to be repeated each time the
vehicle is parked
A single light, a group of
LED lights or another
function of the vehicle is
not functioning The multiplex outputs are
protected in current by an
internal “soft-fuse”. When an
output is shorted, it turns
OFF and stays OFF until the
"soft-fuse" is reset Turn the ignition key to the OFF position
and turn to the ON position again. This
resets all "soft –fuses"
No backlighting in the
instrument cluster Circuit breaker CB10 is
tripped or fuse F20 blown Check / reset circuit breaker CB10
Check / replace fuse F20
The radiator fan clutch
does not function and the
engine is overheating 1. Set the ignition key to the ON
position.
2. Activate the dashboard Telltale Light
Test switch 3 times within 4 seconds.
3. In the engine compartment, set the
starter selector switch to REAR
START and then start the engine
from the rear.
While in this mode, the rear start push-
button can be used to manually engage
the fan clutch. The Multiplex system
knows when the engine is already
running, and it will not activate the starter.