2001 Explorer won't shift into 4 wheel drive

[timkn]

All of a sudden My explore won't shift into 4 wheel dive. any suggestions as to why?

 

[imp]

All of a sudden My explore won't shift into 4 wheel dive. any suggestions as to why?

Which controls do you have on the dashboard, 2WD, 4X4 HIGH, 4X4 LOW, or
4X4 AUTO, 4X4 HIGH, 4X4 LOW?

Check the appropriate fuse which feeds 4X4 shift motor first. If fuse is blown, replace it, try operation. If OK, good to go. If fuse is good, shift motor may be faulty, or connections to it bad. imp