Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSTOYOTA2005CELICA GT-S, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)HEATING, VENTILATION & A/C (HVAC)HVAC CONTROL SYSTEMSAIR CONDITIONINGAIR CONDITIONING AMPLIFIERON-VEHICLE INSPECTION

2005 Toyota Celica GT-S, Standard

On-Vehicle Inspection

2005 Toyota Celica GT-S, StandardSECTION On-Vehicle Inspection

REMOVE COMBINATION METER
(See COMPONENTS )
REMOVE ECM

INSPECT A/C AMPLIFIER CIRCUIT

Disconnect the connector from the combination master and inspect the connector on the wire harness side, as shown in the chart below.

Test condition:
1. Turn ignition switch to ON
  
  Fig 1: Identifying ECM Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TESTER CONNECTION SPECIFIED CONDITION

Tester connection	Condition	Specified condition
A7 - Ground	Constant	Continuity
A6 - A18	Evaporator temperature at 25 °C(77°F)	1.5 kΩ

If circuit is as specified, try replacing the amplifier with a new one. If the circuit is not as specified, inspect the circuits connected to other parts.

Connect the connector to combination master and inspect wire harness side from the back side, as shown in the chart below.
1. Test condition:
  - Run engine at idle speed
  - Set on manifold gauge set
    
    Fig 2: Inspecting Wire Harness Side From The Back Side
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
If circuit is as specified, try replacing the amplifier with a new one. If the circuit is not as specified, inspect the circuits connected to other parts.
Inspect the wire harness side connector of ECM from the back side, as shown in the chart below.

Fig 3: Inspecting The Wire Harness Side Connector Of ECM From The Back Side
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If circuit is as specified, try replacing the amplifier with a new one. If the circuit is not as specified, inspect the circuits connected to other parts.

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.