The hvac fan on my 98.5 A4 goes nuts quite frequently and I don't know why. I nearly always leave the fan on "manual" and select the lowest setting and pop the sun roof or something. Next thing I know I hear some noise look down and the fan has jumped back up to 50 - 80%. I crank the thing back down but it may or may not stay. Dealer says it showed no fault codes so they dunno, nor do I. Anybody seen this or is it the operator?
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I also have the same "problem". The line I get from our Audi tech is that the fan setting is relative and not absolute... meaning that although you set it for manual, it still controls it to some degree.

- A.

nt

I'm glad (or am I) that someone else has a similar problem. I can understand there excuse to some degree. Although it seems rather hokey to me that it tries to make such radical corrections. And the next follow up indicates they don't have the problem.... maybe were just lucky :-) Tanx for the follow up.
P

I just cruised the FAQ section and found an interesting write-up on this. Check it out.

Its in FAQ | Interior | Climate Control

- A.

tanx (nt)

According to Christian Long (in the faq you pointed out) under "manual" the fan shouldn't budge from the setting once you have set it??? Well it don't seem to be so, at least for us. One fear is that this is normal behavior. I don't think its too far fetched and it assumes your dealer may be correct at least to some degree. I could live with that although as I said I think its hokey. My other fear is that that my hvac is not hokey but its broke, cause if it is I want it fixed before the warrantee dies! I hope to hear more from owners to get a confidence level of whether its hokey or broke?
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Mine does it too.. I'll set the fan speed and sometimes, and notice it has changed a few minutes later. The best "logic" I can figure out is that you don't tell the fan what speed to go but suggest a speed. It will sometimes change the fan to keep the cabin temp around the set temperature. I have also noticed after "correcting" the fan back to the speed I want it does not appear to change again. It's odd but some engineer must have had some plan there.

brian
97 A4

What follows are my observations:

I don't care what it says in the owner's manual, in "manual" mode the fan settings are only *offsets* from what the climate control computer thinks it needs from the fan in order to attain the desired (selected) temperature. "Auto" simply represents zero offset. You may get more predictable results if you adjust the desired temperature setting instead of trying to adjust the fan speed. Only adjust the fan speed if it is a bit too high (too loud for instance) or a bit too low (when it is 104F outside). This needs to be better explained in the owner's manual.

**Note to Audi: In my opinion, for the owner's manual to refer to this offset mode as "manual" mode is very confusing. Either call it "offset" mode (pick your favorite synonym), or change the way the current system behaves. If you refer to "manual" mode, people will expect to have full (100%) control of the fan operation. This is simply not the case with the climate control system in the A4. "Full manual control" of the fan is impossible with the current system (except to turn it off completely).

I hope this helps.

Paul

When I wrote that "Auto" represents zero offset, I was referring to the lack of a "man" indicator in the display.

Pressing the "Auto" button is anoter matter entirely, and affects much more than just the fan!

I think most people will realize that, but I thought I should make the clarification anyway.

Paul

NT

Tanx everybody. I recon it aint broke.... But I'm with you its not described well in the op manual. I suspected it was as you mentioned an "offset" since it commonly jumps up or down one bar (Audi is in control here). :-)
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