Volvo Repair: Gear Selector switch, volvo dealer, neutral position

Question
I have 2005 S40 2.4i. Recently I have been getting a message on the dash
screen which reads "Gear Selector Service Required." At first it was just a
message, but after a couple days of driving, the shift lever started to act up.
IT can shift from park to drive with no problems and park to reverse fine, but
when trying to shift from reverse to drive or drive to reverse the lever gets
stuck in the neutral position. I can get it out of the neutral position by
manipulating the "unlock button" with the valet key and the car seems fine
other wise. I have taken it to two dealer ships for diagnostics, and both of
them have said that the gear selector module needs to be replaced. I would
like to know what this module is and how essential it is to the vehicles
operations. I suspect it might be a short caused by water damage inside the
car. The gears seem to shift with no problems in both manual and automatic
mode, it's just physically moving the lever from reverse or drive through
neutral.

Answer
why do you thing is water damage?  gear shift module is the  panel were you shift gears  under that is all one unit comes with new display for gear shifting  that is you gsm module  gear shift module  they do go bad you need that module so they car know what gear you selected so it can response also  if you spill something on them will go bad and  they just go bad by it self   i would go with Volvo dealer recommendation and also  when you do it  perform total can upgrade  software upgrade it will help you in future problems with other parts new software is always good i hope this helps don't forgot to rate me  that would be your thank you to me