View Full Version : AC Fan randomly changing speeds..HELP!

03-20-2012, 12:14 PM
So I bought my 01' A4 (B5) quattro about 3 months ago and hadn't really realized this problem until recently cause I haven't needed the AC or Heater. The problem is that when I turn on the AC/Heater and set the fan to 1-bar (speed/pressure) it will stay at one bar for a random amount of time and then slowly begin to increase..2 bars..3 bars...etc. Usually I don't realize it right away until my contacts start drying up on my eyes I look down and the heat is on full blast lol.

Anyone else have this problem or perhaps know what is going on? Maybe some sort or AC sensor?

Any help/suggestions would be greatly appreciated :)

03-20-2012, 12:17 PM
are you using it correctly? if you put it on automatic, the fan will adjust to the temperature you have set

03-20-2012, 12:27 PM
The HVAC on our cars are climate controlled, and don't have a power level you can set it at. When the fans wind down, it is simply adjusting to whatever temp you have the inside cabin set to. This would apply to both heat and A/C. above the climate control center, there are a couple slots that look like vents. That is where the inside cabin temps are read.

03-20-2012, 12:55 PM
When this happens I am not using the "Auto" setting, that would make sense if the fans changed speed to assist the process.

It seems strange that I would not be able to set it at a certain speed - pretty sure every car I've ever been in you can do this. Essentially when I'm setting the car at 69 or 70 and putting the fan to 1 bar, eventually it will make its way up to 3-4 bars and blasting in my face...This just doesn't seem like the correct functioning. Am I wrong? Going off of what you said, I'm thinking maybe I need a new air temp sensor?

03-20-2012, 01:00 PM
Your system is running normal. Get used to it. As long as it blows both cold and hot, don't worry too much.