Removing the GM3 module from the E39 5-series
Removal procedure for E53 X5
The GM3 module is located behind the glove box, but, you don't need to remove the glove box to get to it.
1) Go in the trunk and disconnect the negative terminal on the battery. You don't want to disconnect the module while powered.
2) There is a black plastic panel located below and behind the glove box. Grab this panel from the very back and pull straight forward. It should unclip and fall away.
3) The GM3 module is visible just above
the panel with three bundles of wires connected. If the
glove box was removed it would look something like the picture below which is
from the X5.
3) Now disconnect the cables from the module. The large connector,
#1, has a sliding locking mechanism. At first this one slides easy then it gets
really rough. You may want to insert large screwdriver and help it that last
1/2 inch. The other two connectors, #2 and #3, have a latch that needs to be
rotated out of the way. There is a small locking tab at the top that needs to
be pressed down before the latch will move.
4) Once the connectors are disconnected move them out of the way and slide the GM3 module forward and down. There should be just enough room to get it out.
BMW General Module III (GM3) Page