Some cars the dome light stays on for a period after you get in or out. When you are in and insert the key and turn the ign the light goes out...
If that's not the case and it always stays on look at the light it's self and see if there is a selector on it, I don't think our years have one but won't hurt to check.
The other thing is on the headlight switch, turn the knob to the left I believe. One way brightens the cluster the other way dims it....if you turn it all the way bright it turns the dome light on.
2004 F150 4x4 Lariat Supercrew, 5.4l, Black/Arizona Beige (daily driver)
2002 Mustang GT Convertible, triple black, mach 1000 system (Summer Car)
2001 Ranger Edge 4x4 xcab (sold to cousin)
4.10 Gear/RPM thread