Replacement or you can try disassembly and repair.  Some have claimed
(temporary or limited) success.

http://tinyurl.com/6ndb8

-Fred W

We plugged in one those electronic air cleaners in a car. The SID
started to fade out.  We thought we were in for a replacement.  Then we
notice the problem started when the electronic device was plugged in.
Guess what happened when we unplugged the air cleaner?   If you have any
aftermarket electronic device plugged into a power outlet near the SID,
consider this a possibility before you replace the SID. I don't know if
a cell phone can cause problems with a SID, but my Nextel Motorola will
drive any speaker/telephone system crazy.

Good job. All SID's are all junk. Saab prides itself on this. Saab
doesn't care even though the must know of this defect in ALL their cars.
 My next car will be Japanese.

It's a flawed design...

I finally got sick of mine and took it into work where we disassembled it.
At the heart of the issue is the flex coming from the main controller board
to the display unit.  The flex is "hot bar" soldered into place on the edge
of the board, but because of the very sharp turn, there is considerable
stress on the flex.

What happens is that the flex delaminates, with the pads that are soldered
to the main board coming off the flex.  In the end, the stress and probably
thermal expansion cause the very fine traces that come through the flex to
disconnect from the pads.  If all you have wrong is the pads delaminating
from the flex you can apply pressure (like in the fixes you find on the net)
and it'll hold them down.  But if you are unlucky to have had the traces
break from the pads, you're out of luck there is really nothing you can do.

A couple of guys at work and I took the thing apart and looked at the flex
under one of our microscopes used for fixing surface mount components.  It's
very clear what happened and why it went wrong.

Unfortunately, Saab wont' step up to the plate and fix this systemic
failure.  I had mine (99 9-5) replaced last year, it's about $400 for the
whole deal (remember, it has to be programmed with the TECH-II to make it
work properly so buying a used one may or may not work depending what car it
came from)  I wrote a letter to Saab about it, they told me that hte ony way
that they'd talk to me aobut it was if it was at a dealer getting repaired,
they and the dealer may choose to do something

read that, if you spend a lot at your dealer, get your car fixed there all
the time, bought the car there and maybe another one, the dealer may kick in
with Saab to make it right.  If you must moved in from out of town and
bought hte car used in the first place, forget it.