BE sure to replace rear side marker lamps (194) in upper side of each taillight lens..They are hard to see and I had the same problem. Replaced both ( one on each side) and failure report cleared.
Replace the bulbs
Yep
yes
Typically this is a failure of the headlight switch assembly. See the question about how to replace the headlight switch in a 1991 Cherokee for the answer of how to accomplish.
Yes
Need a special socket. They are located in the exaust manifold(s).
Hard to see, but on my 96 Jeep Gr Cherokee there are two small screws next to each lamp on the outside.
The regulator is part of the engine computer. You will have to replace the computer.The regulator is part of the engine computer. You will have to replace the computer.
It would be far cheaper to replace it with a used one than to rebuild the existing one.
Not without major modifications. The transmission, wiring, computers, etc are all different.
How to replace spark plugs in a 1989 jeep cherokee?
replace the sensor located behind the grill front center 3 screws in grill and one in the sensor.