Circuit Description
WARNING: This page is about a different car, the 2003 Isuzu Rodeo Sport, 2003 Isuzu Rodeo, and 2003 Isuzu Axiom. However, it is still accessible from the selected car via links, so may be relevant.
When air conditioning and blower fan are selected, and system has a sufficient refrigerant charge, a 12-volt signal is supplied to the A/C request input of the PCM. A/C request signal may be temporarily canceled during system operation by the electronic thermostat in the evaporator case. When A/C request signal is received by PCM, PCM supplies a ground from A/C compressor clutch relay if engine operating conditions are within acceptable ranges. With A/C compressor relay energized, voltage is supplied to the compressor clutch coil. PCM will enable the compressor clutch to engage whenever A/C has been selected with engine running, unless any of the following conditions are present:
- Throttle is open 90% or more.
- Ignition voltage is less than 10.5 volts.
- Engine speed is more than 4500 RPM for 5 seconds.
- Engine coolant temperature 257°F (125 °C) or more.
- Intake air temperature is less than 41°F (5°C).
- Power steering pressure switch signals a high pressure condition.