Remove the grill around the wipers, make sure to get all the screws, some are hard to find, but when you get all the screws the grill lifts off and exposes the wiper assembly. Remove wiper arms, nuts are under a cap at the base of the wiper arm. Unplug the electric assembly. Remove all mounting bolts from the wiper assembly and it will lift out. This works for a 2000 f150 so it is probably the same for 1998.
Take it to a Ford Dealer.
check fuses or relays
To replace a windshield wiper motor for a 1998 F150, first remove the bottom trim on the window. Then remove both wiper blade assemblies and all screws on the metal cowling. Remove the retaining clip from the wiper motor linkage and pull the controls rods off.
If the windshield wipers are not working in a 1998 Ford F150, the cause could be a blown fuse. There could also be a problem with the vacuum hoses connected to the wiper motor or the wiper motor itself.
Check fuses and relays
There is a C clip that holds them on.
top of the fire wall under the hood your wiper arms will connect
How do I replace the block heater in my 1998 F150 4.6L?
lower the tailgate, remove the 2 screws on the side when you lower the tailgate, pull assembly out and replace
No, 97-03 F150's have a 5x135 lug pattern.
With engine oil filter change ( 6 quarts ) according to the Owner Guide
no. Make sure wiper is in "OFF" position before you turn off your car.