4 wheel drive does not engage, the buttons on the dash board which engage 4 wheel drive and low range do not engage. Could it be a fuse or someting more serious?
4 wheel drive does not engage on 1990 Ford Bronco
There's a mode shift switch that takes about 1/2 hour to change Airtex part # ( Four wheel drive switch # 1S4283 ) Start your troubleshooting with this.
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There's a box under the passenger side near the glove box that has a few wire harnesses in it pull it out tap on it the contacts stick and wont allow power to the transfer case motor