@Alan Mancus posted:sounds like the FET that controls the light is shorted so light can't turn off! The board could be repaired! you could take the board to a ASC tech and he could test it and or repair it for you!
Alan
It turns off fine when used with a diesel file as a "ditch light". Just won't work with a steam file with the LMK softkey. Does it have anything to do with the fact the board is from a diesel and now in a steam engine?