TROUBLESHOOTING WITHOUT A DIAGNOSTIC CODE - CONTINUED
Table 8. AC System Troubleshooting - Continued.
TEST OR INSPECTION
2. The thermostat switch is held closed or Replace compressor as necessary (WP
there is a short in wire to magnetic
Cycle or Clutch Will Not
clutch and magnetic clutch will not
Disengage. Air Flow to
release. Check wire that goes to
Operator's Compartment is
magnetic clutch. Wire may have an
Very Cold or Air Flow May
be Restricted Completely at
Times - Continued.
N OT E
Compressor Clutch is
Engaged but System Has
A restriction in liquid line can be detected by running a hand along line until
there is a change in temperature. A change in temperature in line will usu-
ally indicate location of restriction.
1. Check for proper restriction.
(a) Check low and high pressure gage
during operation of AC.
(b) Start engine. Operate engine at
1,400 rpm. Move temperature
control knob to Maximum position
and fan to HIGH position. Close
all windows and doors. In order to
stabilize system, operate system
for a minimum of 10 minutes (TM
(c) The outlet on accumulator should
1. If low side reading is above 50 psi (345
be cold to touch. If outlet is not
kPa), replace inline dryer (WP 0224
cold, check readings on manifold
2. If low side reading is into vacuum,
check for a plugged orifice tube or a
restriction inline (WP 0224 00).
3. If problem still exits, go to Test 2.
2. Check that system is properly charged
1. Recover refrigerant (WP 0225 00),
(WP 0222 00).
evacuate, and charge system with
correct amount of refrigerant. Measure
refrigerant by weight (WP 0225 00).
2. After system is charged, operate for a
minimum of 10 minutes (TM 5-3805-
291-10) and perform Performance
verify correct operation of AC system.
3. If problem still exists, go to Test 3.
3. Check drive belt for damage or
1. If belt is loose or damaged, replace belt
2. If problem still exists, go to Test 4.