For 1990-2009 cars

### Test Description

The number(s) below refer to the step number(s) in the diagnostic table.

1. There are two blower motor supply voltage circuits at the blower motor relay. Probe the circuit that is connected to the blower motor resistor assembly.

2. There are two ignition 3 voltage circuits at the HVAC control assembly. Probe the circuit that is the supply voltage to 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 perform the HVAC Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Manual
2 |

1. Turn ON the ignition, with the engine OFF.
2. Place the mode switch in the vent position.
3. Place the blower motor switch in each speed position.

Does the blower motor operate in any speed position?

Go to Blower Motor Malfunction

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Disconnect the blower motor.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the blower motor supply voltage circuit of the blower motor and a good ground.
5. Place the blower motor switch in the minimum speed position.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4 | Test the ground circuit of the blower motor 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 9
5 | Test the blower motor supply voltage circuit between the blower motor and the blower motor relay 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 6
6 |

1. Turn OFF the ignition.
2. Disconnect the blower motor relay.
3. Turn ON the ignition, with the engine OFF.
4. Place the blower motor switch in the minimum speed position.
5. Probe the blower motor supply voltage circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 7

7 |

1. Turn OFF the ignition.
2. Disconnect the HVAC control assembly.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the ignition 3 voltage circuit of the HVAC control assembly and a good ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 11

8 | Inspect for poor connections at the harness connector of the blower motor relay. 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
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 connector of the 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 15 | Go to Step 14
11 | Repair the ignition 3 voltage circuit of the HVAC control assembly. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 15 | --
12 | Replace the blower motor relay. Did you complete the replacement? | Go to Step 15 | --
13 | Replace the blower motor. Refer to Blower Motor Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | Go to Step 15 | --
14 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . 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 3