Diagnostic Aids
Recirc will only operate for approximately 10 minutes when selected. After 10 minutes the recirc door switches to the outside air position. The tone of the blower and the velocity of the air speed may be noticeably different when the recirc actuator switches positions. This is a normal condition. If excessive air speed change is noticed inspect the cabin air filter for contamination or blockage.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step verifies that the HVAC control module Fan Up Switch parameter matches the requested state of the blower motor switch.
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This step verifies that the HVAC control module Fan Down Switch parameter matches the requested state of the blower motor switch.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor operates in at least one speed position. | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Does the scan tool indicate that the Fan Up Button parameter changes state? | -- | Go to Step 3 | Go to Step 10 | |
Does the scan tool indicate that the Fan Down Button parameter changes state? | -- | Go to Step 4 | Go to Step 10 | |
4 | Place the blower motor switch in each speed position. Does the blower motor operate at the desired speeds? | -- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 5 |
5 |
Does the voltage measure within the specified range? | 10-14 V | Go to Step 6 | Go to Step 8 |
6 |
Does the voltage measure within the specified range? | 4.5-5.5 V | Go to Step 9 | Go to Step 7 |
7 | Test the control circuit of the blower motor control processor for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 9 |
8 | Test the battery positive voltage circuit of the blower motor control processor for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the blower motor control processor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 |
10 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 |
11 | Repair a high resistance in the ground circuit of the blower motor control processor. Refer to Circuit Testing . Did you complete the repair? | -- | Go to Step 14 | -- |
12 | Replace the blower motor control processor. Refer to Blower Motor Control Processor Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
13 | Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 14 | -- |
14 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |
