It is going to be one of a few things. First thing to check is the battery terminals. Look for loose or corroded terminals at the battery. If after cleaning them with a wire battery terminal cleaner brush, and tightening them it still will not start, have the battery checked to see if it is good. If the battery is good, then have the starter checked.
To find out if a 2000-2004 Jeep Grand Cherokee power steering gear box will fit on a 1999 Jeep Grand Cherokee, call your nearest DIY auto parts store
your local parts store or a junkyard
Dealership or any auto part store.
Auto Parts Store Dealer Junk Yard
In a service manual at a parts store or the library.
You'll find repair manuals at your local auto parts store.
go to the parts store and ask for a belt for that vehicle
The running lights on the 99 Grand Cherokee are optional they do have a place to put in a fuse inside the engine compartment on most 99 Grand Cherokees. Although does not include the fuse go to a local auto store to get one.
Purchase a Haynes manual from an auto parts store.
it depends where you are in the world eg America or a chryslerjeep parts store
you have to hook up a scaner and press code reset or a auto zone store will do it for you
By a Haynes Manual at your local part store. The procedure w/ pictures will be in there.