wheel bearing
is the humming coming from the front end of the vehicle? i have a 1996 explorer with the same issue. yes the noise come from the front but not all the time seems to make the humming noise when it gets hot
Humming noise on the front passenger side of a 1997 Ford Explorer XLT may be due to a bad tire. Try to jack up the tire and spin it by hand to see if the noise is there.
Take it to a repair shop and get it fixed!
Check and see if your power steering fluid level is low.
When you turn the wheel, or while you drive?
idle air control valve
have seen in the past , fuel pump moan/noise on this make & model / from a ford tech.
A busted motor mount, for one.
battery is dead
when braking i get a cliking noise my mechinic checked this out but found nothing
a lifter
Not enough info. What kind of noise? Coming from where? Under what situation(s) does it occur?