Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Make sure to perform the HVAC diagnostic system check. If DTCs B0434, DTC B3764, and the auxiliary blower motor is always ON, then the 5-volt reference circuit of the auxiliary HVAC door actuators is pulled low to ground. The DTC diagnostic must be performed to ensure circuit is tested.
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This step tests for an internal failure of the rear seat audio (RSA) control module, or the auxiliary HVAC control module.
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This step tests the 5-volt reference supplied by the auxiliary blower motor control processor.
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This step tests for an internal failure of the front auxiliary HVAC control assembly.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The auxiliary blower motor operates in at least one, but not all, speed positions. | ||||||||||||
Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |||||||||
2 |
Important: Place the blower switch on the front auxiliary HVAC control assembly in the AUX. position. Place the MODE selector in any position except AUTO. Failure to do this may result in a misdiagnosis.
Does the auxiliary blower motor operate properly in each speed position for both the front auxiliary control assembly and the RSA control module? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | ||||||||
3 | Does the auxiliary blower motor operate properly from only the front auxiliary control assembly? | -- | Go to Step 5 | Go to Step 4 | ||||||||
4 | Does the auxiliary blower motor operate properly from only the RSA control module? | -- | Go to Step 7 | Go to Step 6 | ||||||||
Does the Rear HVAC Fan Speed parameter change with each command? | -- | Go to Step 17 | Go to Step 14 | |||||||||
Does the voltage measure within the specified range? | 4.5-5.5 V | Go to Step 17 | Go to Step 13 | |||||||||
Does the Blower Switch Pos. parameter increase within the specified range? | 0-15 | Go to Step 17 | Go to Step 8 | |||||||||
8 |
Does the voltage measure at least 5 V? | -- | Go to Step 12 | Go to Step 9 | ||||||||
9 | Measure the voltage of the 5-volt reference circuit of the front auxiliary HVAC control assembly to a good ground. Does the voltage measure at least 5 V? | -- | Go to Step 11 | Go to Step 10 | ||||||||
10 | Test the 5-volt reference circuit of the front auxiliary HVAC control assembly for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 17 | ||||||||
11 | Test for a high resistance in the low reference circuit of the front auxiliary HVAC control assembly. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you correct the condition? | -- | Go to Step 22 | Go to Step 17 | ||||||||
12 | Test the auxiliary front blower switch signal circuit between the front auxiliary HVAC control assembly and the auxiliary HVAC control module for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 15 | ||||||||
13 | Test the control circuit of the auxiliary blower motor control processor for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 16 | ||||||||
14 | Inspect for poor connections at the harness connector of the RSA control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 18 | ||||||||
15 | Inspect for poor connections at the harness connector of the front HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 19 | ||||||||
16 | Inspect for poor connections at the harness connector of the auxiliary blower motor control processor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 20 | ||||||||
17 | Inspect for poor connections at the harness connector of the auxiliary HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 21 | ||||||||
18 | Replace the RSA control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||
19 | Replace the front HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||
20 | Replace the auxiliary blower motor control processor. Refer to Auxiliary Blower Motor Processor Replacement . Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||
21 | Replace the auxiliary HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||
22 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 | ||||||||
