Acura Integra 1998 Service Manual page 1483

Fans (cont'd)
- How the Gircuit Works
When the ignition switch is in ON (ll), voltage is
applied to the coils of the radiator fan relay and the
condenser fan relay (with A,/C) through fuse 17.
Whenever a ground is provided to the radiator fan
relay and condenser fan relay, the relays are
energized, turning on the radiator fan motor and
condenser fan motor. The relays can be grounded
by the radiator fan switch, engine or powertrain
control module (ECM or PCM) (USA), or the A,/C
and heater lan switches via the A'lC pressure switch
and the A,/C lhermostat.
A,/C Thermostat
The A,/C thermostat is located on the evaporator
housing. The A/C thermostat turns oft the A/C
compressor clutch it the temperature at the
evaporator goes below 3'C (37"F). This prevents
condensalion from freezing on the evaporator fins
and blocking the air delivery into the passenger
compartment. lt the temperature goes below 3'C
(37'F) turning off the A"/C thermostat, and the
BLU/RED wire at the A,/C diode was the only wire
providing ground to the condenser and radiator
fan relays (A,/C switch on, heater fans switch on,
radiator fan switch open, and ECM or PCM fan
controi output not grounded), the relay will
deenergize removing voltage from the condenser
and radiator fan motors causing them to stop
running.
A,/C Pressure Switch
The AJC oressure switch is located in the condenser
outlet line where refrigerant is in a high
temperature/high
pressure liquid state. The A,/C
switch turns off the A,/C compressor clutch if it
senses abnormally high or low pressure. lf the A'lC
pressure switch opens, and the BLU/RED wire at
the A/C diode was the only wire providing ground
to the condenser and radiator fan relays (L/C switch
on, heater fans switch on, radiator lan switch open'
and ECM or PCM fan control output not grounded),
the relay will deenergize removing voltage from the
condenser and radiator fan motors causing them to
stop running.
A./C Diode
This diode orevents the radiator fan switch f rom
grounding the "A'lC ON" input to the engine or
powertrain control module (ECM or PCM).
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting
procedures.
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