I have a 92 bronco w/ push button 4wd and the funniest happened. I live in the northeast and recently we had a couple of snow storms. The first one the 4wd system worked great, however the second storm I went to go into 4wd and it wouldn't go. For some reason I believe that the transfer case/ engaging motor was literary frozen, by ice b/c the day before the storm I went to the car wash. So I looked under the transfer case and it was full of ice and snow, so I put the truck in doors and the next day it went into 4wd with no problem. Has anyone ever heard or experienced this problem.

When I worked at a garage in Wyoming I had a similar problem with a customer's vehicle. In that case it was a matter of moisture in the electrical connections where the wires plug onto the motor. We took them off and cleaned then and reinstalled them with silicone dielectric.... availible at any parts store. I imagine it would be possible to get moisture inside the motor and freeze it but I would rather guess that the motor is weak and may need replacing. It takes more energy to engage them in the cold than it does if it is warm outside. I hope this helps... Good luck.