Cooling Fan Connections; Electronic Ground - PREVOST H3-41 Maintenance Manual

SECTION 06: ELECTRICAL
CAUTION
The Multiplex vehicle uses a VF4 relay
specially designed for Volvo that has different
internal characteristics than the current VF4
relay. It is important to use only the new part
marked Volvo as a replacement in Multiplex
vehicles. Regular relays have an inadequate
lifespan for Multiplex vehicles.
2.9

COOLING FAN CONNECTIONS

FIGURE 6: COOLING FANS CIRCUIT BREAKER BOX -
CONNECTOR NUMBER
FIGURE 7: COOLING FAN IDENTIFICATION
20 PA1621 Maintenance Manual All Series | Revised Sept 2019
WARNING
WHEN THE ENGINE IS RUNNING...
Cooling fans may start running at any
moment.
Keep hands away from cooling fans or keep
the radiator door closed.
WARNING
Cooling fans may be running when the
engine is shut down in the following
conditions:
• If a High
condition exists
regeneration). The CAC fans will keep
running for a maximum of 15 minutes.
During the Electric Motors Test
•
Sequence, the cooling fans will start
running briefly.
The CAC fans and the radiator fans are
controlled by two multiplex modules, i.e. AE49 &
AE52. Each module controls one (1) CAC fan
and three (3) radiator fans. For this reason, if
one module fails, sufficient cooling will still be
available for the CAC and the radiator through
the second module.
Module AE49: Fans 1, 4, 6, 8
Module AE54: Fans 2 3, 5, 7
If one fan doesn't function, diagnose the
probable causes of failure for this particular fan.
If one CAC fan and three radiator fans are not
functioning, then you should suspect that one of
the multiplex modules (AE49 or AE52) is
defective.

2.10 ELECTRONIC GROUND

All the electronic modules installed on this
vehicle are grounded to the electronic ground
stud located in the main power compartment,
using separate and protected circuits.
All the loads fed by a particular electronic
module are grounded to that same module.
However, a load can be grounded to another
module in the situation when the load can be
powered by two
redundancy need.
Exhaust Temperature
(e.g. following
different modules for