For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Heater Blower Controls System Check performed? | -- | Go to Step 2 | Refer to Heater Blower Controls System Check
2 | Inspect the blower electrical connections and grounds. Refer to Heater Blower Controls Schematics . Is the action complete? | -- | Go to Step 3 | --
3 |

1. Sit inside the vehicle.
2. Close all of the doors and windows.
3. Turn the ignition switch to ON.
4. Set the blower speed to HI.
5. Set the mode to VENT.
6. Set the temperature control to full COLD.
7. Cycle through all of the blower speeds, modes, and temperature control positions in order to determine where any noise occurs and where it does not occur.

Is the blower making a constant whine, tick/click, flutter or scrapping noise that lessens with a lower blower speed?

--

Go to Step 5

Go to Step 4

4 | Listen to the blower again. Is the blower making a squeal/screech noise at the start-up only and/or intermittently? | -- | Go to Step 5 | Go to Step 8
5 | Inspect for blower motor and fan vibration at each blower speed by feeling the blower case. Is the vibration excessive? | -- | Go to Step 7 | Go to Step 6
6 |

1. Remove the blower from the blower case. Refer to Blower Motor and Fan Replacement .
2. Inspect for foreign material at the opening of the blower intake.

Does any foreign material exist?

--

Go to Step 11

Go to Step 7

7 |

1. Inspect the blower fan for the following conditions:

• | Wear spots

• | Cracked blades

• | Cracked hub

2. Inspect the fan retainer and the fan alignment.
3. Inspect the blower case for wear spots.

Does any evidence of wear or damage exist?

--

Go to Step 12

Go to Step 13

8 |

1. Set the blower speed to HI.
2. Test the full HOT to full COLD temperature positions in the VENT, HEAT, and DEFROSTER modes.

Is the excessive blower noise in VENT mode only?

--

Go to Step 14

Go to Step 9

9 | Listen to the blower again. Is the excessive blower noise in the HEAT and/or DEFROST modes only? | -- | Go to Step 15 | Go to Step 10
10 | Listen to the blower again. Is the excessive blower noise in every mode but not at every temperature position? | -- | Go to Step 16 | Go to Step 17
11 | Remove any foreign material from the blower assembly. Repair as necessary. Is the action complete? | -- | Go to Step 18 | --
12 | Repair the blower fan and/or the blower case as necessary. Is the action complete? | -- | Go to Step 18 | --
13 | Replace the blower motor and fan. Refer to Blower Motor and Fan Replacement . Is the action complete? | -- | Go to Step 18 | --
14 |

1. Inspect the air ducts for any obstructions and foreign material.
2. Inspect the vent door seals.
3. Repair as necessary.

Is the action complete?

--

Go to Step 18

--

15 |

1. Inspect the air ducts for any obstructions and foraging material.
2. Inspect the heater and/or the defroster door seals.
3. Repair as necessary.

Is the action complete?

--

Go to Step 18

--

16 | Inspect the temperature door seals and repair as necessary. Is the action complete? | -- | Go to Step 18 | --
17 | Inspect the heater system for any obstructions or foreign material between the blower fan and the temperature door. Repair as necessary. Is the action complete? | -- | Go to Step 18 | --
18 | Perform the functional test. Refer to Function Test . Is the action complete? | -- | Refer to Heater Blower Controls System Check | --