This is probably a 9004 halogen bulb but to be sure just go to your local parts store and tell them that you need a new headlight bulb for a 1998 Jeep Cherokee.
changing the bulb
Yes , according to the 1998 Mercury Mountaineer Owner Guide : ( the headlight bulb is # 9007 )
9004
the headlight assembly needs to come out in order to replace the bulb.
1998 Grand Caravan headlight bulb replacement: Purchase the correct replacement headlight bulb(s) first, before disassembling the vehicle. See sources and related links below for replacement bulb information. Then consult your owner's manual for the headlight bulb replacement procedure. As simple as it sounds, the owner's manual is the best place to start for bulb replacement instructions and illustrations. You may want to consider replacing both left and right at the same time in order to keep brightness and color equal (optional).
the headlight assembly needs to come out in order to change the bulb ive had to do that to my 98 as well.
drop the bumper and take the headlight housing out
are you trying to change the entire headlight assembly? or just the bulb.
High and Low Beam Headlight - 9007Fog Lights - H3Boslla offers high-performance Led headlight bulbs for these bulb sizes.
On a vehicle with high intensity discharge headlight, hid, that is an indicator of a failing bulb.
9004
H1