The numbers below refer to the step numbers on the diagnostic table.
The High speed blower motor control circuit is spliced to the Blower motor resistor circuit. A short to voltage on the control circuits will open the HVAC Blower fuse. Be sure to check all the blower motor control circuits for a short to ground.
The ground circuit to be tested comes from the HVAC blower relay.
Check the connection by removing and securely reinstalling before replacement of the HVAC control is considered.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor is inoperative in all speed positions. | |||
1 | Did you perform the HVAC Diagnostic System Check? | Go to Step 2 | |
2 |
Does the blower motor operate in any speed position? | Go to Blower Motor Malfunction | Go to Step 3 |
3 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 4 |
Test the blower motor supply voltage circuit for an open, short to ground or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 5 | |
5 | Test the High blower motor control circuit 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 11 | Go to Step 6 |
Test the ground circuit of the HVAC control assembly for an open, short to voltage or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 8 | |
7 | Inspect for poor connections at 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 11 | Go to Step 9 |
Inspect for poor connections at 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 11 | Go to Step 10 | |
9 | Replace the blower motor. Refer to Blower Motor Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | Go to Step 11 | -- |
10 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | Go to Step 11 | -- |
11 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |