where is the hazard fuse (relay) located on a 1999 Mercury Mystique

Might be under the hood or inside the glove box or on the side of the dash on the drivers side

it should be under the steering wheel or it might be in the engine compartment on the left side near the master cylinder.or call the ford dealer they are made by the anyway.

Are you sure it is not a flasher? Check under dash on driver is side in fuse panel the flasher should be round replace with another flasher. This should take care of your problem.

on the turn signal switch itself... if not, should be a yellow relay under drivers side...