changing the bulb
the headlight assembly needs to come out in order to replace the bulb.
Yes , according to the 1998 Mercury Mountaineer Owner Guide : ( the headlight bulb is # 9007 )
drop the bumper and take the headlight housing out
You replace the bulb the same as a 1998, which is answered further down the page.
the headlight assembly needs to come out in order to change the bulb ive had to do that to my 98 as well.
you open the hood and grab the bulb and turn it , it should pull out, the unplug the wiring harness, install is reverse.
Replace headlight bulb only when blown.
On older vehicles you replace the entire headlight. On the newer vehicles you just replace the bulb unless the headlight assembly is damaged.
See the following site:
replace the low beam headlight bulb
How do you replace headlight bulb on 2004 Mazda Tribute?
How do you replace a 1999 Ford Escort headlight bulb?"