SECTION 22: HEATING AND AIR CONDITIONING
DOB 1300-1556 | X3-45 Commuter PA-1648 Maintenance Manual First release Oct 2020
• Severe liquid refrigerant flood back.
• Oil slugging caused by an overcharge of oil
or flood starts.
• Discharge valves not seated properly (liquid
drain back during shutdown).
Broken Suction Valves
Symptom:
• Loss of unit capacity at all temperatures.
• Compressor unable to pull extremely low
vacuum with suction shutoff valve front
seated.
Cause:
• Repeated liquid refrigerant flood back.
• Flooded starts.
• Overcharge of oil.
• Discharge valves not seated properly (liquid
drain back during shutdown).
• Expansion valve not controlling properly.
Unloader Valve Stuck Open
Symptom:
• Loss of unit capacity at all temperatures.
• Higher than normal suction pressure.
• Even cylinder head temperature.
Cause:
• Unloader body stem bent.
• Foreign material binding unloader piston or
plunger.
4.2 BRUSHLESS EVAPORATOR MOTOR
The brushless evaporator motor is installed in
the evaporator compartment (Figure 22). It is a
27.5 volt, 2 HP (1,5 kW) motor which activates a
double blower fan unit.
FIGURE 22: X3 SERIES EVAPORATOR COMPARTMENT
4.2.1 Removal
• Set the battery master switch to the OFF
position and trip circuit breaker CB3.
• Open the evaporator compartment door.
• On the HVAC module. Disconnect circuit
90H1 from evaporator relay R12.
• Identify the discharge ducts inside
compartment and remove the Phillips head
screws fixing the air duct to blower fan unit.
• Remove the motor access panel.
• Disconnect electrical motor speed control
wire power cable and ground cable from
motor terminals.
• From under the vehicle, remove the eight
bolts fixing the double blower fan unit base.
Remove the complete unit from the
evaporator compartment (Figure 23).
CAUTION
Never support evaporator motor assembly by
its output shafts while moving it. Always use
double blower fan unit base.
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