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Symptom Chart

SYMPTOM CHART

Condition Possible Sources Action
No communication with the electronic automatic temperature control (EATC) module (19980)
  • Circuitry short/open.
  • EATC module communication network.
 Go To PINPOINT TEST E .
The EATC system is inoperative, intermittent or incorrect operation
  • Circuitry short/open.
  • Input sensor(s)/erratic input signals.
  • Charging system.
  • Automatic temperature control sensor hose and elbow (19D888).
 Go To PINPOINT TEST F .
Incorrect/erratic direction of airflow from outlet - manual climate control
  • No vacuum to the A/C control (19980).
  • Function selector switch (19B888).
  • Vacuum hose/kinked/pinched.
  • Airflow door binding/stuck.
  • Vacuum control motor (18A318).
  • A/C vacuum check valve (19A563).
  • A/C vacuum reservoir tank and bracket (19A566).
  • Vacuum actuator arm not connected to the door crank.
  • Heater control valve (18495) leaks vacuum.
 Go To PINPOINT TEST G .
Incorrect/erratic direction of airflow from outlet - EATC
  • No vacuum to the A/C control (19980).
  • Function selector switch (19B888).
  • Vacuum hose/kinked/pinched.
  • Airflow door binding/stuck.
  • Vacuum control motor (18A318).
  • A/C vacuum check valve (19A563).
  • A/C vacuum reservoir tank and bracket (19A566).
  • Vacuum actuator arm not connected to the door crank.
  • Heater control valve (18495) leaks vacuum.
 Go To PINPOINT TEST H .
Insufficient, erratic, or no heat
  • Low engine coolant level.
  • Engine overheating.
  • Plugged or partially plugged heater core (18476).
  • Temperature blend door binding/stuck.
  • Temperature blend door actuator (19E616).
  • Incorrect heater control valve (18495) operation.
 Go To PINPOINT TEST I .
The air conditioning (A/C) is inoperative/does not operate correctly
  • fuse(s).
  • Circuitry short/open.
  • A/C cycling switch (19E561).
  • A/C system discharged/low charge.
  • A/C pressure cutoff switch (19D594).
  • A/C control (19980).
 Go To PINPOINT TEST J .
Insufficient air conditioning (A/C) cooling
  • Low refrigerant level.
  • Temperature blend door actuator.
 CARRY OUT the refrigerant system tests. REFER to REFRIGERANT SYSTEM TESTS .
If OK, Go To PINPOINT TEST A  for vehicles equipped with EATC or if equipped with manual climate control, Go To PINPOINT TEST L .
The air conditioning (A/C) is always on
  • Circuitry short/open.
  • A/C cycling switch (19E561).
  • Function Control Switch (19B888).
 Go To PINPOINT TEST K .
No operation in all the temperature settings - manual climate control
  • Temperature blend door actuator control (19D816).
  • Temperature blend door.
  • Temperature blend door actuator motor (19E616).
  • Circuitry open/shorted.
 Go To PINPOINT TEST M .
The blower motor is inoperative - manual climate control
  • Circuitry open/shorted.
  • A/C blower motor switch (19986).
  • A/C blower motor resistor (19A706).
  • A/C blower motor (19805).
 Go To PINPOINT TEST N .
The blower motor is inoperative - EATC
  • Circuitry short/open.
  • Blower motor relay (14N089).
  • A/C blower motor (19805).
  • A/C blower motor speed control (19E624).
 Go To PINPOINT TEST O .
No operation in high blower setting - manual climate control A/C blower motor resistor (19A706).
A/C blower motor switch (19986).		 Go To PINPOINT TEST P .
The blower motor does not operate correctly - manual climate control
  • Circuitry short/open.
  • A/C blower motor resistor (19A706).
  • A/C blower motor switch (19986).
  • Blower motor relay (14N089).
 CARRY OUT the blower motor resistor component test in this section. If the blower motor resistor tests good, Go To PINPOINT TEST Q .
The blower motor operates continuously in high speed - manual climate control
  • Circuitry short.
  • A/C blower motor resistor (19A706).
  • A/C blower motor switch (19986).
  • Blower motor relay (14N089).
 Go To PINPOINT TEST R .
The blower motor does not operate correctly - EATC
  • Circuitry short/open.
  • A/C blower motor speed control (19E624).
  • EATC module (19980).
 Go To PINPOINT TEST S .
The steering wheel control switch is inoperative/does not operate correctly
  • Circuitry short/open.
  • Steering wheel control switch.
  • EATC module.
  • Redundant steering control module.
 Go To PINPOINT TEST T .
The temperature set point does not repeat after turning the ignition switch OFF - EATC
  • fuse(s).
  • Circuitry short/open.
  • EATC module (19980).
 CHECK circuit 298 (VT/OG) for a short or open and repair as necessary. If okay, INSTALL a new EATC module.
The temperature display will not switch between Celsius and Fahrenheit - EATC
  • EATC module.
 PRESS the MAX A/C and DEFROST buttons simultaneously for at least 0.75 second. If the temperature display does not switch between Celsius and Fahrenheit, INSTALL a new EATC module.
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