Ok problem number gazillion

2005 A6 4.2l Q

As soon as it got warmer my AC has been acting weird, sometimes it works but most of the time cold air only comes out of the left vent next to the gauges however all the other vents have warmer air. Also, sometimes it will randomly start blowing supper supper cold air when its not so hot out from all the vents even when turned to say 76.

Is this a faulty temp sensor on passenger side?

Also, in the beginning of the summer i noticed that the main fan in the dash was making a noise like something was hitting it. It did this for about 20 minutes, then whatever was hitting it sounded like it went threw it, it was a soft but loud fan churning noise. However, it did not sound like it was anything heavy, more like some paper.

Could there be debris in there blocking something?

Any help or advice is greatly appreciated as always

 

I would imagine the exterior temp sensor is bad, if the outside temp is below a certain temp, like 30*, it will shut off the A/C compressor. If it thinks its hotter than it is outside it may shut off the A/C in antisipation of a pressure overload. Pull the fault codes out of the A/C control head using a VAG COM. Don't have a vag? Buy one!

 

There is a TSB on the different temperatures coming from the driver side when compared to the passenger side. There is also a TSB on different temperatures from the side vents when compared to the center vents. Drop me a PM with your e-mail address, referencing which problem you are experiencing, and I will e-mail you the TSB.

As far as the fan noise, I had the same problem on my 05 4.2 twice during the past 4+ years. Both times it was the pollen filter that had somehow become dislodged and was leaning up against the fan blades.

 

Hello All,

I have been experiencing trouble with my Exterior Temp, which resulted in the Climate Control trying to warm up the car while it was about 15 °C outside (about 60 F).

My Exterior Temp in the dash was displaying -9 °C (about 15 F), so the Climate Control was trying to warm up the interior... Had to open windows and shut off A/C... Was getting a little too warm in there !

Questions:

From the previous posts in this thread, I deduct that I have a faulty Exterior Temp Sensor. Where is that Temp Sensor located on my 2001 A4 2.8 quattro?

If I have to change that sensor, is it available in some Internet stores ?

If it is not the Sensor, can this trouble indicate problems with the A/C system or other thermostat problems ?

Thanks !

Frank

 

Frank,
the Exterior Temp Sensor is located in the front bumper, lodged in right behind the lower grill. The location is somewhat in the middle area of the bumper. I'm pretty sure if you take the belly pan off and get under the bumper, you should be able to locate the sensor's wire and follow it.

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on a 01 It looks a little different then Chefro's though, it's black and is just hanging out in front of the radiator in a plastic clip. Mine is bad and I get a fault code for it. But I haven't tested it yet. It could be a crushed wire the way they run along the bumper cover like that.