55-8HEATER, AIR
AND VENTILATION Troubleshooting/On-vehicle Service
Engine (Non-turbo)>
12
Sensor ground
Automatic compressor-ECM power
supply (output side)
Fin sensor power supply
o v
The ignition switch, blower switch andBattery positive
switch areall ONvoltage
The ignition switch, blower switch and
A/C switch are all ON
TROUBLESHOOTING HINTS
l R e f e r t o C O O L I N G S Y S T E M
SHOOTING.
Refer to
Terminal No.Name of Signal
Check requirements Terminal voltage
compressor clutch relay
When the compressor ON conditions Battery positive
are satisfied voltage
2Automatic compressor-ECM groundov
4Automatic compressor-ECM power
The ignition switch, blower switch and Battery positive
supply (input side) switch are all ONvoltage
5Automatic compressor-ECM powerTheignition switch is ONBattery positive
voltage
Engine (Turbo) and Engine>I
O N - V E H I C L E S E R V I C E
SIGHT GLASS REFRIGERANT LEVEL TEST
The sight glass is a refrigerant level indicator. T o check the
refrigerant level, clean
sight glass and start the vehicle,
engine. Push the button to operate the compressor, place
the blower switch to high and move the temperature control
dial to max cool. After operating for a few minutes in this
manner, check the sight glass.
1.If the sight glass is clear, the magnetic clutch is engaged,
discharge line is warm and the compressor
suction line is cool; the system has a full charge.
2.If the sight glass is clear, the magnetic clutch is engaged
and there is no significant temperature difference between
compressor suction and discharge lines; the system has
most of its refrigerant charge.
3. If the sight glass shows foam or bubbles, the sy stem
could be low on refrigerant or the receiver drier is restricted.
The system has to be tested, leak checked then rech arged
with refrigerant.
TSB RevisionI
