I've replaced the locks on a 93 sentra and 95 200sx.  I got a kit for under
$200 which included all locks (door, trunk, etc.).  Lot of work to change
them all (and drill out the steering column lock/screws).  The switch
attaches to the back of the lock assemble with one phillips screw, so if
that had been my problem it would have been easy (if you can get just the
switch from parts).

Gary K

Of course I've never done this on a Max/I30...