How to hook up my alternator to battery on ford expedition 98

Nicole Gonzales this does not sound like an alternator issue per se unless of course your (new) battery is empty. Check the battery connectors post and see if the wires are corroded etc. Let us know if your vehicle starts with a boost from another vehicle etc. Try to use a multimeter and check to see if you get power to the starter. ALWAYS MAKE SURE THAT YOU SECURE THE VEHICLE SO IT DOES NOT ACCIDENTALLY MOVE!!!! Check something like this and let us know what you find out. Ultimately a quick attempt to hit wire the starter will show if that works. If so you need to check the starter relay and see if you get power to that.

Let us know what engine you have in your Expedition so we can see if there are any know issues with it

SInce you specifically ask for the wiring here is the wiring diagram for a 1998 Ford Expedition