Re: Seat heater switches

[Huw Powell <human@nh.ultranet.com>]

> No.  There is only _one_ heater wire - the backrest and squab are wired
> in series, and there's only one circuit back to the controller.
> 
> I suspect the switch presents on/off and six different resistances
> to the controller.  The controller applies a voltage to the switch
> resistance and to the thermistor in the seat element.  All it would
> have to do is amplify the delta current and apply it to a relay via
> a diode.

I suspect it's more likely to just be a varying (several fixed)
resistance in series, judging by the way this sort of thing works
elsewhere on Audis... but the resistors, like with the rad fan and the
heater fan, will be hidden somewhere.  I should bow out of this
discussion since I am totally clueless, not having heated seats myself
(I took a harness out of a 4kq once) and not ever even seeing the car in
question...

but it was fun guessing along for a while.

-- 
Huw Powell

http://www.thebook.com/human-speakers/audi-main.htm

the steering wheel isn't connected to anything, it's just a place to
rest your hands