od light
I just purchased a 250 SD had the same problem, decided to swap the switch with the one in my f150 (same switch) . swapped them out and worked good, put the bad switch in the 150 guess what it worked? scratched my head a little, decided to swap them back out to original location both work guess the contact pins had a little corrosion or something I would suggest pulling the switch out check the contacts and reinstall.