Schematic Reference: HVAC Air Delivery/Temperature Control Schematics

Steering Wheel Controls

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check

1. Turn ON the ignition, with the engine OFF.
2. Turn ON the radio.
3. Press each entertainment steering wheel control switch.

Do the entertainment steering wheel controls function?

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Go to Step 3

Go to Symptoms in Entertainment

1. Turn OFF the ignition.
2. Disconnect the radio.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the steering wheel controls input circuit to a good ground.
5. Press the TEMP UP and TEMP DOWN steering wheel control switches.

Does the voltage change for each switch pressed?

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Go to Step 4

Go to Step 17

Is the vehicle equipped with a CD changer?

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Go to Step 5

Go to Step 6

1. Turn OFF the ignition.
2. Connect the radio.
3. Turn ON the ignition, with the engine OFF.
4. Operate the CD changer functions from the radio.

Do the CD changer controls function?

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Go to Step 10

Go to Symptoms in Entertainment

1. Turn OFF the ignition.
2. Connect the radio.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the serial data E&C circuit of the DLC connector to a good ground.

Does the voltage measure above the specified value?

3 V

Go to Step 7

Go to Step 9

1. Turn OFF the ignition.
2. Disconnect the heater and A/C programmer (HCM).
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the serial data E&C circuit of the DLC connector to a good ground.

Does the voltage measure above the specified value?

3 V

Go to Step 8

Go to Step 13

1. Turn OFF the ignition.
2. Disconnect the radio.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the serial data E&C circuit of the DLC connector to a good ground.

Does the voltage measure above the specified value?

3 V

Go to Step 11

Go to Step 14

1. Turn OFF the ignition.
2. Disconnect the heater and A/C programmer (HCM).
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the serial data E&C circuit of the DLC connector to a good ground.

Does the voltage measure above the specified value?

3 V

Go to Step 16

Go to Step 12

Test the serial data E&C circuit for an open between the radio and the HCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 20

Go to Step 16

Test the serial data E&C circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 20

Go to Step 16

Test the serial data E&C circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 20

Go to Step 15

Test the serial data E&C circuit for an open between the radio and the HCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 20

Go to Step 15

Test the serial data E&C circuit for an open between the radio and the HCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 20

Go to Step 16

Inspect for poor connections at the harness connector of the radio. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 20

Go to Step 18

Inspect for poor connections at the harness connector of the HCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 20

Go to Step 19

Replace the steering wheel control switches. Refer to Steering Wheel Control Switch Assembly Replacement in Steering.

Did you complete the repair?

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Go to Step 20

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Replace the radio. Refer to Radio Replacement in Entertainment.

Did you complete the repair?

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Go to Step 20

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Replace the HCM. Refer to Programmer Replacement .

Did you complete the repair?

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Go to Step 20

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Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2