Mine didn't work when I bought it. I was just looking for a better vehicle, knowing I had a 600 mile move coming my way. Using primarily the city newspapers, Nashville had the Tennessean in the early AM and the Banner in the afternoon. I had been given an 87 Ranger 2wd, and I am not certain the engine, but the truck was from MN and was rusted near to death. It was sitting dead on side the road beside the fellas house, and I went by the next afternoon and began tinkering with it. Not long until I brushed the ground to the starter and it fired right up. It had NO brakes, but it was a standard stick shift so I took off home, maybe 5 miles, anyway. long story, I drove it several years after getting it resurrected.
In that length of time I had came to know Fords current standing and was looking only in the ads under Ford, F150 and Ranger columns. At least two I had seen like an early Sunday morning cruise sitting at a car lot and swiped a finger into the tail pipe and it came out far too smutty.
Early one morning I took a 4 am drive downtown and got a paper soon as they brought out the first stack to the machine at their front entrance, and after looking it over I had one new one to check. At that time papers were still the best way to find one, and I knew to get there fast or any good one would be gone. I called at 8 and the woman had just got home from a night shift at the sheriff's dispatch and her husband had just left but she agreed to let me come see it.
Not advertised as a 4WD, and when I arrived she pointed it out and she went back in for a minute. I did the finger swipe in the tailpipe, looked ok, then under the driver side to see any leaks, loose wires etc, and first thing I noticed was a transfer case and front drive shaft.
She had not advertised 4WD because it wasn't currently working and she told me it needed something that cost $100.00 she had been told. Doing my own work on them did not let that worry me.
In spite of that and 230,000 miles I got her to follow me home to leave my older truck, past the bank where I got the money and at her house I counted it out.
I had just got a very nice deal ALL because of that silly thing not coming on like it should, when the ONly thing it generally needs is an occasional twist or button pushed and then retracted to hear it click
BTW Speedo, I have another vehicle, a 96 Explorer I found on a more current site a couple years ago, that had a transmission going out and finally blew, but I had bought it primarily for the engine. I never used it in 4WD, but might have attempted to in checking it out
Anyway you mentioned that dash switch and the Explorer has the knob that turns like the one you asked about. I think it does the same thing, only in a different way as does the push button