Loss of Fan control from Climate Control, 87 5kcstq

[Michael Murphy]

Motor Sport Visions Photography wrote:
> 
> The subject line pretty much tells all. My climate control blower fan is
> doing the opposite of the usual failure (the fan is only ~3 years old
> and runs fine) in that as of yesterday it started running at full speed
> regardless of the CC setting (yes, it even ran full blast on the "off"
> position). The problem is intermittentent (aren't all Audi electrical
> issues?). The opposite problem/cure seems simple, change the blower
> fan...this no doubt gets more involved. I know there is a speed control
> box someplace and will sit with book-o-Bentley and properly troubleshoot
> this when I have time and will report the fix to the list...I was just
> hoping there could be a BTDT shortcut I could follow.
> 
> TIA for thoughts and suggestions.

A simple voltage check at the blower motor connection will reveal the
blower is getting +12VDC all the time.

Oran might right.  The blower control unit might be kaput...but it
doesn't hurt to check the signal coming to it from the CC head. 
Remember, when you first turn on the CC, it will run at "hi-speed" fan
so there's a possibility the "low" button on the CC head needs a
cleaning.  The good news is you don't have to spend 3-?? hours replacing
the blower... the bad news is both the CC head and the fan speed
controller cost more than the blower unit to replace.
--
Mike Murphy