Simple to Replace.....
The replacement is really quite easy.
On the 231 Transfer Case, the 4WD switch is located at the front of the TC, driver's side, on top. You have to be a little dexterous to get in there with a wrench (must reach up over the skid plate & around the front driveshaft) but once you set it up it's quite easy( a mirror is a must to see what you are doing). Just unplug the electric connection...(at this point, you can short out the two terminals in the plug with a paper clip, turn your key to "on", and the dash light should come on to indicate that you are in 4WD)....at this time it is NOT necessary to put the selector lever in 4WD.
If the light goes on, the switch is not working. (You can test the switch by using a meter w/ a continuity setting....push the ball in and you should get continuity through the two terminals....if not, the switch is bad. Do this before you install the new one. You may have another problem and could return the switch if unused).
Now, slide an open end wrench on to the hex base of the switch, all you need is a little room to break open the threads and the rest is simple. Be sure that there isn't any debris laying on the top of the TC that can get into the TC when the old switch is removed. I used an air jet to clean the area. Ensure that the "o" ring is in place and screw the new one in place & "lock" it in. Maybe a 1/2 - 1 hour job max. Be sure to hook up the electric connection (I always put a little veseline on the rubber seal).
Check the 4WD light by turning the key to "on" and place the 4WD selector in 4H. Light should go on.
Refer to my original post...mine didn't (what a surprise). Hence, the investigation.
What fun...........It doesn't get any better than this.
Let us know how you make out.