1. Disconnect the automatic temperature controller (ATC) connectors A and B.
2. Disconnect the blower motor control module.
3. Measure the resistance circuit GRY/BLK from terminal 4 of the blower motor control module to terminal B20 of the ATC controller.

Does the resistance equal the specified value?

0 ohms

Go to Step 2

Go to Step 6

Measure the resistance in the circuit from terminal 1 of the blower motor control module to terminal B9 of the ATC controller.

Does the resistance equal the specified value?

0 ohms

Go to Step 3

Go to Step 6

1. Reconnect the wiring harness to the ATC controller and to the blower motor control module.
2. Turn ON the ignition, with the engine OFF.
3. Measure the voltage from ground to terminal B20 of the ATC controller.
4. Cycle the fan speed controller manually from the lowest, speed 1, to the highest speed 5.

Do the voltages measured match the specified ranges?

Speed 1:8.3-9.3 V

Speed 2: 6.3-7.3 V

Speed 3: 3.9-4.9 V

Speed 4: 2.2-3.2 V

Speed 5: 0-0.5 V

Go to Step 4

Go to Step 5

Replace the ATC controller. Refer to Heater and Air Conditioning Control Replacement .

Is the repair complete?

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System OK

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Measure the resistance in circuit PNK between terminal 6 of the power transistor and the blower motor terminal 2.

Does the resistance equal the specified value?

0 ohms

Go to Step 7

Go to Step 6

Repair or replace the wiring harness for the circuit PNK.

Is the repair complete?

--

System OK

--

Inspect the wiring harness of the motor and power supply.

Is there any problem in the wiring, the relay, or the fuse?

--

Go to Step 9

Go to Step 8

Replace the blower motor control module. Refer to Blower Motor Control Module Replacement .

Is the repair complete?

--

System OK

--

Repair or replace the wiring harness, the relay, or the fuse as required.

Is the repair complete?

--

System OK

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