headlights

1997 Jeep cherokee's headlights went out at same time. Highbeams work, and i've checked all fuses. My owners manual is for a 1997 but the jeep is really a 1996 and the diagrams for the fuse display and relays is completely different. Unsure if i should change both headlights or if it is an electrical problem. any advice would be great, thanks joe