I have a 2007 Q7 and I am experiencing problem with air blower located below the dashboard passenger seat. I assume it distributes both air conditioned and hot air? I started the engine up and after 2-3 seconds of delay blower starts up and runs smoothly for anywhere between 10-30 seconds and then it slowly loses speed and it diminishes to nothing. I had it apart and there was a lot of dust and residue inside the motor. I used contact cleaner to flush and clean armature and rotor. It looked like new and I honestly didn't see any issue but the dirt. I assembled blower back into location, started it up and problem reacurred. I haven't check blower itself if it's firmly attached to the motor shaft to eliminate free spinning. I would appreciate anybody's input with same experience and also I have a question about the blower's resistor. If they have a reputation to break down and if so what is the symptoms of a faulty resistor and how does it affect the blower?

Thanks

 

Check the voltage & ground circuits when the blower is running & see what happens when is starts to cut out.
Remember , the blower resistor is responsible for blower speed controlled from the push button controller.

 

There are two buttons operating speed. One is auto and one is marked as windshield switch. Are these the buttons you are referring to?

Is there a way to bypass the resistor with jumper without compromising the motor and proving a faulty resistor?

I had it running fine for at least 30 mins and than after the speed was lower and barely running. I assume if it was the motor it just wouldn't run at all?

 

You should have 2 wires going directly to the blower motor. 1 is power & 1 is ground. Ground is usually brown or black , the other will be colored differently. Disconnect the plug from the blower & power it up by itself. Just don't back feed anything back to the car.

 

I had a similar problem 2009 Q7. So I ordered a Blower Motor Resistor, and replaced it. How ever that didn't change anything. So then I ordered a Blower Motor and replaced it, now it works just like new. I tried to check the voltage and got no reading even when the car was on, so checking the voltage probably wont work. Changing the motor itself fixed my problem.

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