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Trouble with 2005 Outback

I need some help? I have a 2005 Subaru Outback Turbo, and I am somewhat car savvy, but I am stumped. This car has about 160k miles on it and it has a high pitched sound from the heater fan. It actually lowers in pitch as the fan increases in speed. At high speed you almost cant hear the sound.

Now I have tried replacing the fan, but that did not help. I have removed the fan wires to make sure the sound is coming from the fan, and with the fan disconnected the sounds goes away (of course the fan doesn’t work with the wires off). I really don’t know what could be causing this sound.

I know Frank and Ray would say to turn up the radio, or leave the fan off, and I have tried both, but eventually I would like to see if there is a real fix.

Anyone have an idea??

More than likely, the problem is the resistor pack that controls the fan speed.
When the resistor pack goes flukey, it will emit a high-pitched whine.

There’s two parts in that area that can cause a mechanical whine. The fan motor. Or the fan itself, the squirrel cage thingy that rotates and blows the air. Something that cage gets to knocking on the side of one of the supports. Try moving the fan and see if it is hitting something. This can often be fixed by simply moving it up or down along the shaft of the fan motor so it no longer hits. Sometimes it isn’t the fan, it’s the motor. The motor bearings might be getting dry. (Dry bearings on the fan itself are possible too.) You might try to test the motor separate from the fan, if you can separate the two parts temporarily.

As mentioned above, the associated electronics can emit a whine too. This should be considered a possibility as mentioned by @VDCdriver, as the symptom of the whine frequency going down with fan speed is uncommon when the problem is the fan motor or fan itself. The power to the fan is split between the motor and the resistors, with more going to the motor in high speed, and more going to the resisters in low speed. When the fan is going at the highest speed, less power is being dissapated in the resistor packs, and that might cause the pitch to go down, which would be consistent with an electronics problem, not a mechanical problem.

@GeorgeSanJose, the guy replaced the fan. In most cases, the fan and motor are one preassembled unit.
@philipmw did you get a fairly decent quality blower motor?

Replaced the fan and motor (one piece) with an original one from Subaru. I am sure the problem is electrical not mechanical, as you have mentioned. The big question is how do I fix it? Where is the resistor pack and how do I replace it? thanks for all the help, we might be getting to the bottom of this.

@philipmw the resistor pack should be somewhere near the blower motor.

Look for this.

Was the blower motor under the glove box?

I’m pretty sure that the motor’s switch, in its highest position, circumvents the resistor pack.
There’s no current going through it, in that position.
That, and I’ve never heard of resistors making an audible noise.

You’ve replaced the motor and the fan, then?

“I’ve never heard of resistors making an audible noise.”

While it has been quite a few years since I had a car with that problem, I do recall that we focused on the resistor pack as a result of strange noises coming from the area of the HVAC fan. The noise was–IIRC–sort of a screeching or whining noise. Replacing the resistor pack eliminated that noise, and it never came back.

So, based on my experience with this issue, I would say that a bad resistor pack can emit some strange noises.

Yes I have replaced the motor and fan, Thank you all for the help I will look for the resistor pack.