SECTION 22: HEATING AND AIR CONDITIONING
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016)
11
The evaporator fan motor, located in the
evaporator compartment, is protected by a 90
amps, manually-resettable (CB3) circuit breaker
located on the rear junction panel and is
accessible from the engine compartment curb-
side door, on R.H. side of the vehicle (refer to
Section 06,
“Electrical System”
in this manual for
details).
The condenser coil mounted on the condenser
compartment door is ventilated by four axial
fans. The fan motors are protected by a
manually-resettable 70 amp circuit breaker
(CB7) mounted on the rear junction panel and
accessible from the engine compartment curb-
side door.
Furthermore, the following relays, diodes and
multiplex module are located in the evaporator
compartment. They are mounted in the HVAC
module located inside the evaporator
compartment on top of the fan housing (FIGURE
4 & FIGURE 11).
FIGURE 11: HVAC MODULE
A/C Junction Box
Multiplex Module
A54 I/O-B
Relays
R10
Condenser fan power
R12
Evaporator fan power
R20
Water circulating pump relay
R26 Water
Preheater
Relay
Diodes
D8
Parcel rack Liq. Sol. Valve
D9 Water
circulating
pump
D10 Water
circulating
pump
D11
Pass. Liq. Sol. Valve
D17 3
rd
Bagg.Cmpt Lights
D19 2
nd
Bagg.Cmpt Lights
D20 1
st
Bagg.Cmpt Lights
Relevant Breakers
CB15
15A, Condenser fan up-fore
CB16
15A Condenser fan down-fore
CB17
15A Condenser fan up-aft
CB18
15A Condenser fan down-aft
4. HVAC UNIT BASIC MAINTENANCE
Basic maintenance required on the passengers’
and driver’s units consists in cleaning their
respective coils and cleaning or replacing air
filters.
However, periodic inspection for broken drains,
hoses and charging of system should be done.
MAINTENANCE
Squeeze rubber discharge tubes located
underneath the appropriate compartment to
eliminate the accumulated water and dirt
every three months.
4.1 COIL CLEANING
Check the external surface of the coil at regular
intervals for dirt or any foreign matter.
MAINTENANCE
For the driver's HVAC unit, remove the grill
and the coil access panel. Clean the driver’s
unit evaporator and heater coils with low-
pressure air jet every 100 000 miles, taking
care not to damage fins. Clean the bottom of
the defrost plenum.
FIGURE 12: DRIVER'S HVAC UNIT COIL ACCESS PANEL
MAINTENANCE
With the air filters removed, clean the
passengers’ unit
evaporator and heater coils
with low-pressure air jet or a stream of low-