i agree w/ bobbywolf. the circle method is the easiest and quickest method to find out if it's working or not. all auto's and 5 speeds have the 4wd light, and it's controlled by the front vaccum disconnect, so if the diaphram is bad, or the 4wd is not engaging, the light will not come on. if the light DOES come on, chances are your in 4wd.
95 yj sahara green w/ spice hard and soft top, bikini top,full steel doors, and 2 piece bestop soft doors,tnt customs front tube fenders w/ 6" flare,warn gas tank skid, skidrow oil pan skid,4.0HO,rear 31 spline 8.8 w/ disc brakes,4.10's and lsd,front HP d30 w/ 4.10's and aussie front locker,ax15,np231j w/ jb conversions ss sye, tom woods custom cv d/s,RE 4.5xd,35" toyo open country m/t's, 1" daystar body lift, warn 9.5ti