Tim,
Turn the ignition switch to the on position. The oil light should be on and bright.
Remove the wire from the oil pressure switch. The light should be out.
If the light was on dimly with the key on, remove the wire at the oil pressure switch and ground it to a good (earth) ground and see if the light is bright. If so it is the oil pressure switch.
p.s. I had this problem and it was the oill presure switch..