Yes, that's what they do. Normal behaviour. If two occurrences
constitutes a normal behaviour.

I have a 2001 A4 TS Avant. Mine started feeling warm on the left side of
the driver's cushion (driver's seat on left hand side of the car). Then
it smoked, burned a hole through the seat fabric, scorched my trousers,
then shut off never to work again, regardless of whether I dialled 1, 6,
or 47 on the panel. I still haven't got it fixed.

In your case, it sounds as if it's about to fail. Unfortunately I have
no advice on how to repair *before* it goes but it might be an idea to
stop using it; I wish I had. My reading of the situation is that the
heater element started cracking in one place, leaving a too-thin strip
which could not carry the current adequately, resulting in overheating
prior to complete failure. Quite reasonable when considering that the
outside of the seat takes a beating since that's the first and last
point of contact as the driver enters and exits the car. But I have no
evidence that it's not the heater control (though I doubt it).

You others out there (who actually know, please): to replace the heating
element:
1) do you have to remove a fuse or disconnect battery to reduce airbag
detonation,
2) does the whole seat cushion have to be removed, or can the element be
replaced separately?

3) any idea of cost?

/Robert

Same thing happens to me, A4 1.8T (00').  I'm really getting tired of the
"little" things going wrong with this car.  It's nickle and diming me to
death.

Tim in Portland