For 1990-2009 cars

### Test Description

The number below refers to the step number 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.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor is ON while the blower motor switch is in the OFF position.
1 | Did you perform the HVAC diagnostic system check? | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Manual
2 | Important: The blower motor switch must remain in the OFF position during this diagnostic procedure.

1. Turn ON the ignition, with the engine OFF.
2. Place the blower motor switch in the OFF position.

Is the blower motor OFF?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Disconnect the blower motor relay.
3. Turn On the ignition, with the engine OFF.

Does the blower motor continue to operate?

Go to Step 11

Go to Step 4

4 | Probe the high blower motor control circuit of the blower motor relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 5 | Go to Step 6
5 | Test the high blower motor control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10
6 | Probe the blower motor supply voltage circuit, from the blower motor resistor with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 7 | Go to Step 9
7 | Test the blower motor supply voltage circuit between the blower motor relay and the blower motor resistor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 8
8 | Test the low, medium 1, medium 2, and medium 3 blower motor control circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10
9 | 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 14 | Go to Step 12
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 14 | Go to Step 13
11 | Repair the short to voltage on the blower motor supply voltage circuit between the blower motor and blower motor relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | --
12 | Replace the blower motor relay. Did you complete the replacement? | Go to Step 14 | --
13 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . 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