Just had my 98 1.8T (build date 3/98) in for service, and tech assured me that my mirrors (that have never heated ONCE yet) are functioning properly (he tested). They are indeed designed to only come on below 40 degrees F, as has been reported here. Not all the time, and not triggered by defroster. <p>This is too bad, since in California 40 degrees means they rarely come on at all (unless I go skiing). I want them to come on to clear condensation in the morning (maybe 55-60 degrees F where I live). <p>Anway, question: rather than going to expense of re-wiring, seems like one of the various CONTROL MODULES (probably Climate Control) could be re-coded to have heated mirrors come on at a different temperature, or maybe there is even a code setting to make the mirrors defroster-activated? <p>Anybody yet figured out the options available in the OTHER control modules? As Dean Gibson pointed out below, there are 9 control modules altogether. We have instructions here for re-coding the Central Locking module only. I would think the Climate Control coding might be a real help with some other problems (like the condensor shutting off at 40 degrees, making window de-fogging between 32 and 40 very difficult). <p>Btw, my dealer switched central locking codes at no charge, no argument: said tech had to hook up anyway to re-set the service indicator, so takes about a minute while he's there. <p>Erik <p>

My 98.5 2.8 (built Jan 98) has all the time heated mirrors. I just had both replaced under warranty because they both had stopped working. I wish mine only worked when it was cold. At 90 degree outside temp the mirrors are very warm. I know they heat all the time and my dealer confirmed this. Do the mirrors on the 1.8T work different?? Should mine only work at low outside temps?? The manual states they work at certain tempertures?? I'm confused. How do your mirrors heat? It appears if they are on all the time they do indeed burn themselves out. Once the car is out of warranty this will be an out of pocket expense and no one wants that.<br>Roy M 98.5 2.8q Tip (With full time hot mirrors)

My 98 1.8T has permanently heated mirrors (which have just been replaced after 15,000 miles). **** design IMHO.

How did they test the mirrors unless it was 40F in the dealer garage? I ask this because I really don't know how they could do this unless there IS INDEED a control module interface with the heated mirror system (in which case they could enter the appropriate codes and make the mirrors "think" it is 40F) but from what I have seen and been told of the wiring, I just don't think a control module is involved. I could be wrong, though, and welcome any further comments to the contrary. <br>Also, I don't recall, from all the previous surveys on this subject, *anyone* who has actually witnessed a heated mirror coming on at the described temperature. <br>BTW, my friend's '96 mirrors ONLY come on with the defroster, while my '97 is wired to be on all of the time. No ifs, and or buts...<p>Tom<br>'97 2.8q white

He said there was nothing wrong with my heated mirrors. Drivers side gets SLIGHTLY warm and the passenger side stays cool. He said that they were controlled by the defrost switch (I don't believe him) and that they MIGHT also be temperature controled around 40 deg. The mechanic observed that the drivers side mirror heats from the outside-in and the passenger side heats from the inside-out.<p>Once it starts snowing I am going to take it back in if they still don't work. They get _HOT_ right? Not just lukewarm.<p>$0.02,<br>David

The official wiring diagrams show that the A4's are wired to be on all the time that the engine is running. Some '96's work with the defroster switch (the correct way!). 98.5's are on all the time. There may be a new design, but I'm not aware of it.<p>There are no modules that control the heaters. It is directly wired to the "switched" portion of the power distribution system.<p>The mirrors just pop out of the housing when pryed at the top/bottom/sides. Very easy to do. Disconnect the connectors and measure the mirror with an ohmmeter. New mirrors read 6 to 9 ohms. Bad mirrors will read 100 ohms and up. Anything in between will give degrading performance.

Shame on me for not believing A4.org and listening to my clueless dealer. Enough is enough. I went downstairs and popped off my mirrors. Drivers side (slightly warmer than freezing) measured 29 ohms. Passenger side (freezing cold) 194 ohms. BOTH sides register 12.0V with the ignition turned ON, Defrost OFF, and temp 60 deg F.<p>This settles it. My mirrors are fried. My dealer "tested" both mirrors and said they worked. Liars. They're going to get a visit from my multimeter Monday morning. AOA's getting a call if they so much as blink when I ask for new mirrors.<p>All steamed up,<br>David

Now we all know tht 29 ohms will indicate a mirror heater that is basically not worth using electrons. Wait until you get the new mirrors, you will burn your hand on them. If you have a manual trans car, you can pop fuse #9 to save them but you will lose your outside temp display also. If you have a trip comp. I don't know what you will lose.<p>I was thinking about this last night and all Audi has to do to at least prolong the mirror life is to place a thermal switch in series with the heater lead inside the mirror housing, 10 minute job. This thermal switch can come on at 35 degrees F and probably let the mirror last a few more years! Or come out with heaters that can last being on all the time. Since I rewired my mirrors to come on with the rear defroster switch 2 months ago, I only used them 3 times and they turn off automatically 12 minutes later...should last for over 100 years that way!

Bob,<p>Could I get a copy of your wiring diagram?? I'd like the have that in my hip pocket when I return to the dealer Monday morning. If you have a scanner email them to dpincus@netstream.net or I'll email you with my fax number.<p>THANKS! Let's get this in a FAQ!<p>David