Diagnostic Aids
To prevent evaporator freezing, the recirc door periodically rotates back and forth from the outside air to recirc 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 tests the output of the blower motor switch in each speed position and through each blower motor control circuit.
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Test the circuit that did not illuminate the test lamp in Step 5.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor operates in at least one, but not all, speed positions. | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the blower motor operate at the desired speeds? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
3 |
Does the test lamp illuminate in each speed position? | Go to Step 7 | Go to Step 4 |
4 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 12 |
|
Important: The blower motor switch must be in the correct speed position for the blower motor control circuit being tested. Probe each blower motor control circuit with a test lamp that is connected to a good ground and place the blower motor switch in the appropriate speed position for the blower motor control circuit being tested. When the blower motor switch is in each speed position, does the test lamp illuminate? | Go to Step 10 | Go to Step 6 | |
Test the appropriate blower motor control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 11 | |
7 |
Does the test lamp illuminate in each speed position? | Go to Step 9 | Go to Step 8 |
8 | Test the ground circuit of the blower motor resistor assembly for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 10 |
9 | Inspect for poor connections at the harness connector of the blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 13 |
10 | Inspect for poor connections at the harness connectors of the blower motor resistor assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 14 |
11 | 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 16 | Go to Step 15 |
12 | Repair the battery positive voltage circuit of the blower motor resistor assembly. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 16 | -- |
13 | Replace the blower motor. Refer to Blower Motor Replacement . Did you complete the replacement? | Go to Step 16 | -- |
14 | Replace the blower motor resistor assembly. Refer to Blower Motor Resistor Assembly Replacement . Did you complete the replacement? | Go to Step 16 | -- |
15 | Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 16 | -- |
16 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
