MacDon M105 Operator's Manual page 347

Symptom Problem
Compressor clutch slipping.
Thermostat defective or
improperly adjusted.
Clogged air filters.
Air conditioning
not producing
sufficient cooling.
Heater circuit is open.
(sufficient cooling
defined as when
air temperature in
Insufficient air circulation over
cab, measured at
condenser coil; fins clogged
louvered vent, can
with dirt or insects.
be maintained
at 25°f (14°c)
below ambient
Evaporator fins clogged.
air temperature.)
Refrigerant low.
Clogged expansion valve.
Clogged receiver-drier.
Excessive moisture in system.
Air in system.
Blower motor sluggish in
operation.
Windows fog up. High humidity.
Unit icing up due to thermostat
adjusted too low.
Unit icing up due to excessive
moisture in system.
Unit icing up due to incorrect
super-heat adjustment in the
expansion valve.
Air conditioning
cools intermittently. Thermostat defective.
Defective blower switch or
blower motor.
Partially open, improper
ground or loose connection in
compressor clutch coil.
Compressor clutch slipping.
169890
TROUBLESHOOTING
Solution
Remove clutch assembly for service
or replacement.
Replace thermostat.
Remove air filters, and clean or
replace as necessary.
Close temperature control in cab,
and valve on engine).
Clean condenser.
Clean evaporator fins (under cab
floor).
Contact Dealer.
Run A/C to dehumidify air and
heater to control temperature.
Adjust thermostat.
Contact Dealer.
333
Section
Contact Dealer.
Cleaning Engine
Air Filter Primary
Element, page 235
and
Cleaning
Return Air Cleaner,
page 220
3.10.3 Controls,
page 48
and
3.10.1 Heater
Shut-Off, page 47
Air Conditioning
Condenser, page
221
Air Conditioning
Evaporator, page
222
Contact Dealer.
3.10.3 Controls,
page 48
Contact Dealer.
Contact Dealer.
Revision A