Home/Lexus/RX/Lexus RX I (1997-2003)/Repair manual/Automatic HVAC System/Automatic A/c-Heater Systems: Overview
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Automatic A/c-Heater Systems: Overview Lexus RX I

DESCRIPTION

WARNINGTo avoid injury from accidental air bag deployment, read and carefully follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY article in GENERAL SERVICING.
CAUTIONWhen battery is disconnected, radio will go into anti-theft protection mode. Obtain radio anti-theft protection DTC from owner prior to servicing vehicle.

The automatic A/C-heater system automatically maintains temperature set by driver. The system features automatic fan speed and airflow control, and automatically selects the most suitable fan speed and airflow to control temperature. A/C system is controlled by A/C Electronic Control Unit (ECU), which is incorporated in back of instrument cluster.

Note. A/C ECU may also be identified as Instrument Cluster ECU or Combination Meter ECU.

A refrigerant gas and liquid separator (modulator) has replaced the receiver-drier. Modulator is integrated into one end of condenser. A replaceable drier bag and filter are located inside modulator.

A replaceable air filter, located under glove box, is used to remove dust and other airborne particles from intake air.

NO BLOWER MOTOR OPERATION

  1. Check IG power source circuit. See «IG POWER SOURCE CIRCUIT»(ref-98896-S40633391672001060500000) under SYSTEM TESTS.
  2. Check heater main relay. See «RELAYS»(ref-98896-S17410865562001060500000) under COMPONENT TESTS.
  3. Check body ECU. See appropriate MULTIPLEX CONTROL SYSTEMS article in ACCESSORIES & EQUIPMENT.
  4. Check blower motor circuit. See «BLOWER MOTOR CIRCUIT»(ref-98896-S18778464122001060500000) under SYSTEM TESTS.
  5. Check blower motor control relay. See «RELAYS»(ref-98896-S17410865562001060500000) under COMPONENT TESTS.
  6. Check A/C ECU ground circuit. See «A/C ECU GROUND CIRCUIT»(ref-98896-S01783194692001070900000) under SYSTEM TESTS.