I have a 1999 A4 V6 Quattro that has a nonfunctioning heater blower. The car was given to me, so I don't know what was done to it before I got it, but I've jumpered the fan off a battery to make sure it works and it does. Also I used a voltmeter to check voltage at the plug that connects to it, and found ample current. My question is, is there some seccondary switched current or trigger that could be causing my problem? Also strange is that the heater controls on the dash do this weird thing where the fan speed display(the red digital bars that increase left to right in the heater control screen) constantly rise then completely drop off to zero. Watching this happen, the screen will show the fan speed at the level it was set to, then out of nowhere it will rev down to nothing....and after a few seconds it will wind up to the set speed again, stay there for a few more seconds, then turn off again. IT ENDLESSLY DOES THIS(yet the fan will not actually blow). Does anyone know what could be causing this, and if it's also what's causing my fan to not work? I'm going nuts, and nearly crashing everytimeI drive because of fogged up windows...please help.

 

could be a fuse or relay

 

i checked all the fuses(under the dash and in the engine bay fuse box), not the problem. Also i removed the relaythat's behind the dash/above the glove box, opened and inspected it, and found no visible problem there either. Do you know if there is any other relay or switch or whatever that could be causing this?

 

u check the one on the driver's side between the door and dash? looks like this

 

yeah huh, not the problem(as far as i can tell). The strangest thing is that when i used a voltmeter the the plug(which connects to the blower fan) it showed current in the lines, which makes me wonder if there is either:

-a remote trigger signal of some sort that isn't working properly(since that plug has 5 wires total)

-or a bad connection. If this is the case (and i hear Audis are notorious for loose connectors) does anyone have any clever ideas for making a better electrical connection? I've thouroughly cleaned both ends(plug and fan) with electrical cleaner, scrapers and wire brushes. Does anybody know of a product that increases electrical conduct(ability?), like a grease or something? PLEASE HELP! I'm open to anything, no suggestion is too crazy, because i've already tried everything that popular opinion views as sane.