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CUSTOM AIR CONDITIONING
18-23
4. Temperature 'lever at COLD.
5. Blower on HI.
6. Normal engine idle.
7. "Hand-Feel" temperature of evaporator inlet pipe
near thermostatic switch capillary tube connection AND
accumulator can surface with compressor engaged.
a. BOTH SAME TEMPERATURE AND SOME
DEGREE COOLER THAN AMBIENT--Proper condition:
check for other problems (see A/C System Diagnostic
Procedure).
b. INLET PIPE COOLER than accumulator surface-
low refrigerant charge.
a
Add slight amounts (1/4 lbs.) of refrigerant UNTIL
BOTH feel the same temperature. Allow stabilization time
between additions.
a
Then ddd 14 oz. (1 can) additional refrigerant.
C.
INLET PIPE HAS FROST ACCUMULATION--
Accumulator surface warmer; proceed as in Step b above.
Diagnostic Procedure".
2. Set the control at NORM mode, LO blower.
0
The thermostatic switch should cycle the compressor
off in 5 minutes or less. If the compressor operates
continuously AND the accumulator frosts, this is an
abnormal condition and will lead to evaporator freeze-up.
The problem is either loose clamps around the capillary tube
to the evaporator inlet pipe or a defective switch.
a
If the compressor does not operate, thermostatic
switch is defective (provided that it has been established that
battery voltage is available at one swtich terminal with the
A/C "on"). This, of course, results in no cooling. Replace
the switch.
The thermostatic switch is pre-set and cannot be
adjusted.
When trouble shooting the refrigerant system, refer to
Fig. 1B-20, "C.C.O.T. A/C System Diagnostic Procedure".
THERMOSTATIC SWITCH
DIAGNOSIS
1. Install Gage Set and set up the vehicle as described
under "Performance Conditions" in "C.C.O.T. System
B SERIES A/C DIAGNOSTIC CONNECTOR
Before using these diagnostic charts, check system operation as follows with ignition switch turned ON.
M1
means low
intermediate speed; M2 means high intermediate speed.
Blower Switch
Positions
A/C Control
Operation should be:
Mode Position
Blower Speed
Compressor Clutch
Low, M1, M2, High
OFF
Low only
Off
Low, MI, M2, High
Vent, Heat
Low, M1, M2, High
Off
Low, M1. M2, High
Norm, Bi-Level
&
Defrost Low, M1, M2, High
On
Low, M1, M2, High
Max
High only
On
Look up the sympton in the charts and make the checks
indicated. The connector will allow you to quickly isolate
the problem to a unit (switch, relay, clutch, blower, etc.) or
the wire connecting that unit in the circuit. If the problem
area is a given control (switch or relay) or wire, the defect
can be found by jumpering across the control.
If the jumper makes the system work, the control is
defective. If not, the problem is in the wire or connector. With
the jumper in place, connect a voltmeter from the jumper to
ground. If no voltage is present, fault is in the hot lead. If
voltage is present, the fault is in the other wire.
B SERIES C60 & C65 AIR
CONDITIONING ELECTRICAL
DIAGNOSIS
Ignition switch in ON position, engine stopped and
inside car temperature over 55°F. (1 3°C.).
Blower switch in LOW position and A/C control in
VENT mode unless otherwise noted.
NOTE: Always check connections at a unit before
replacing it.
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