4WD on 96 Passport does not engage

This is a shift on the fly model 3.2 V6 Auto. When I push the 4wd shifter into 4H it does not engage the 4wd. The 4wd light does not come on, and I can feel that it's not engaged.

If anyone has a fix let me know, I'm trying to avoid a dealer visit.

Thanks

:banghead:

The only thing I have seen is the solenoid go bad or have a hose knocked off.I believe it is blue and black and is behind a cover on the front axle.You might take a look and see a hose is off or it has been hit.Someone else may log on with something they have replace but that is the only thing I have seen.Carl