1993 Front Axle Locker

Are you talking about the mechanism that engages the front axle into 4 wheel drive?
 
There is no locker. If you are talking about the vacuum motor, that is to put the front axle into “drive” when selecting 4x4. If you mean an actual differential locker, somebody added that aftermarket and it would be for the improvement of good power and traction to both front wheels all the time offroad.