Step
| Action
| Value(s)
| Yes
| No
|
Important: A constant air rush noise is typical of all heater systems. Some systems
may be louder than others. If possible, inspect a similar vehicle in order
to determine whether the noise is typical or excessive.
|
1
| Was the Heater Blower Controls System Check performed?
| --
| Go to
Step 2
| Go to
Heater Blower Controls System Check
|
2
|
- Inspect all the electrical connections and the grounds for proper
connections.
- If a connection is doubtful, use a voltmeter in order to test
for constant voltage at the blower motor.
Is the repair complete?
| --
| Go to
Step 3
| --
|
3
|
- Sit in the vehicle with the doors and windows closed.
- With the ignition switch in the ON position and the engine off,
start the blower on the HI mode.
- Select full COLD on the temperature rotary knob.
- Cycle through the blower speeds, modes and temperature valve positions
in order to find where the noise occurs.
- Define the noise as one of the following types:
- If possible, compare the noise with another vehicle of the same
model in order to determine if the noise is typical.
Is the noise typically a flutter or a rumble that is constant at high
blower speeds in certain modes, but can be eliminated at lower blower speeds?
| --
| Go to
Step 4
| Go to
Step 6
|
4
| With the blower on HI, inspect the full HOT to the full
COLD temperature positions in all modes.
Is the noise audible in all modes and in all temperature positions?
| --
| Go to
Step 5
| Go to
Step 8
|
5
|
- Check the system for obstructions or foreign materials between
the fan and the temperature valve.
- Remove, repair, or replace the fan and the temperature valve as
necessary.
- Recheck the system for the noise.
Is the noise audible?
| --
| Go to
Step 3
| Go to
Heater Blower Controls System Check
|
6
| Feel the blower armature in order to check for vibration
of the motor and the fan at each blower speed.
Is the vibration excessive?
| --
| Go to
Step 7
| Go to
Step 10
|
7
|
- Examine the blower fan for wear spots, cracked blades, or a cracked
hub.
- Examine the blower case for wear spots.
- Repair or replace parts as necessary.
- Recheck the system for the blower noise.
Did you find and correct the condition?
| --
| Go to
Heater Blower Controls System Check
| Go to
Step 11
|
8
| Is the noise
audible in all modes, but not audible in all temperature positions?
| --
| Go to
Step 9
| Go to
Step 12
|
9
|
- Inspect the temperature valve seals.
- Repair or replace the temperature valve seals as necessary.
- Recheck the system for the noise.
Is the repair complete?
| --
| Go to
Heater Blower Controls System Check
| --
|
10
|
- Remove the blower motor and fan assembly. Refer to
Blower Motor and Fan Replacement
- Check for foreign material at the orifice of the blower inlet.
- Repair or replace the blower motor and fan assembly as necessary.
- Recheck the system for the noise.
Did you find and correct the condition?
| --
| Go to
Heater Blower Controls System Check
| Go to
Step 7
|
11
|
- Replace the blower motor and fan assembly. Refer to
Blower Motor and Fan Replacement
- Recheck the system for the noise.
Did you find and correct the condition?
| --
| Go to
Heater Blower Controls System Check
| Go to
Step 13
|
12
|
- Check the ducts of the noisy modes for obstructions.
- Remove any obstructions.
- Check the seals of the suspected mode air valves.
- Repair or replace the valves as necessary.
- Recheck the system for the noise.
Is the repair complete?
| --
| Go to
Heater Blower Controls System Check
| --
|
13
| Is the noise a click/tick or a whine?
| --
| Go to
Step 14
| Go
to
Step 4
|
14
| Replace the blower motor with a second new blower motor.
Did you find and correct the condition?
| --
| Go to
Heater Blower Controls System Check
| Go to
Step 15
|
15
| Reinstall
the original blower motor.
Is the repair complete?
| --
| Go to
Step 4
| --
|