Why are my window switches staying on?

[Huw Powell]

> > > You want to try something cool?  Leave your ignition off, turn the
> > > headlights on, and then pull the "flash to pass" stick back.  This
> > > will toggle what my friends and I call "phantom power" or something
> > > (actually I forget what we called it).  You will have power for as
> > > long as you hold back the stick.  Pretty cool.
> >
> > No, running accessories off one terminal of the headlight switch will
> > not be cool, it will be hot, and seriously hasten the demise of an
> > already weak link in your cars wiring system.  This is not
> > recommended!
> 
> Does anyone know if this was a "feature" that was advertised, and for what purpose?

I would judge it be an accident - but I do not know if it was actually
promoted as a "feature."  I certainly haven't encountered any references
to it in any of the owner's manuals to Audis I have owned.

> It sure is nice if you are waiting for the driver to return, but you have to roll the
> windows down or up for whatever reason (rain, heat, etc.)

true...
 
> Or, is this characteristic not a feature, but just some overlooked electrical circuit that
> gets created from this series of switch positions?  I'm curious about this now.

The key to this bug or feature is the way the headlight dip switch
works.  The actual hi/lo switch (on the type 85 at least) is located at
the base of the stalk, and is a separate piece, set up to simply switch
the outgoing headlight power to either the high beam fuses or low beam
fuses.   This is all ignition-on only, since the headlight power supply
tot he switch comes from the ignition switch (should be X-relay, and
might sometimes be, but not on the diagram I am working from...)

When you pull on it for flash-to-pass, it sends power out to both
circuits but gets it from the parking light power source - which is of
course a battery direct powered circuit.

Sooooo, when you pull on the flash to pass lever with nothing on and key
out, you make a circuit from the battery supply at the parking light
switch, via the dip switch, back to the headlight switch... which should
only get back to the ignition and X circuits if the headlight switch is
turned "on".  But those things are so melted after a decade that
predicting what they will do is a bit difficult.

All I know is that, especially with unrelayed lights, you are then
running an awful lot of current through the supply wire for the parking
light circuit.

A better way to make a feature like this, would be to add a hidden
switch somewhere that energises the output side of the X relay circuit. 
That won't run the coil, or fuel pump, just the items on the X buss - of
which the windows are the onlyones you're really likely to want to use
with the key not present.  Just fuse the new circuit carefully.

-- 
Huw Powell

http://www.humanspeakers.com/audi/

http://www.humanthoughts.org/