The glovebox light and switch is sold directly from Saab dealers as
as a single assembly for about $25. (Part number 4202 107)
In order to change the glove box light, you will need a Torx
screwdriver (included with your spare tire).

First, clear everything out of your glove box.  Then carefully remove
the screws holding the glovebox to the dash.  Be careful not to prod
around wrecklessly, since there is an airbag.

Once the screws have been removed the glove box drops down
as indicated in the photo below.

The glove box light is on the left side of the glove compartment.
Before removing the glove box light assembly, the electrical cable
harness must be removed. Then the black plastic cover can be
removed by hand as shown below.  The new glove box light
assembly will snap into place.  It should be inserted from the inside
of the glove box.  The cover should be installed from outside of the
glove box.  Don't forget to install the cable harness.  The glove box
light will turn on when the glove box is opened and the key is on.