The number(s) below refer to the step number(s) on the diagnostic table.
This step tests for blower motor operation in any speed setting.
This step tests for voltage at the blower motor.
This step tests for a possible open in the blower motor ground circuit.
This step tests for output voltage from the blower motor switch.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: HVAC Schematics DEFINITION: The blower motor is inoperative in all speed positions. | |||
1 | Did you review the HVAC operation and perform the necessary inspections? | Go to Step 2 | |
Is the blower motor inoperative in each speed position? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 5 | |
Does the test lamp illuminate? | Go to Step 9 | Go to Step 8 | |
Important: The blower motor switch must be in the correct speed position for the blower motor control circuit being tested. Failure to do this will result in a misdiagnosis.
Does the test lamp illuminate? | Go to Step 10 | Go to Step 6 | |
6 | Test the HVAC module ignition 3 voltage circuit for an open, high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 7 |
7 | Test each blower motor control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 |
8 | Test the ground circuit of the blower motor resistor assembly for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | 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 in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | 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 in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 14 |
11 | Inspect for poor connections at the harness connectors of the 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 15 | Go to Step 12 |
12 | Replace HVAC module. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | Go to Step 15 | -- |
13 | Replace blower motor. Refer to Blower Motor Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | Go to Step 15 | -- |
14 | Replace blower motor resistor assembly. Refer to Blower Motor Resistor Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | Go to Step 15 | -- |
15 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |