its on the front fuse box... its marked.
BR
On a 1998 Buick Regal LS, the starter relay switch is typically located in the under-hood fuse box. You can find the fuse box on the driver's side, near the front of the engine compartment. The relay itself is usually labeled, and you may need to consult the owner's manual for the exact location and identification of the starter relay within the fuse box.
were can i locate and replace a starter for a 1998 buick regal?
Possibly... Under the air filter
I'm assuming its like other buick regal models, around the passenger side windshield wiper.
How do you take off a radiator for a 98 Buick Regal
Look at the rear of engine right side
How do you remove 1998 Buick regal ls sun visor
4T60-E
Under the vehicle just in front of the left rear tire.
Try "Google"
Usually they are in the glove box, but they could be located on the floor, in front of the seat, on the drivers side, or on the drivers door itself. The 1998 Buick Regal unfortunately does not have a manual trunk release. There are kits available to add a manual trunk release, however.