I agree it being a battery problem. Had the same thing happen to my 3d cell several years ago. If you still have the light, you might try what worked for me.
Take one end off (either side), stand light vertical and fill it with Coke (the drink)
. Let sit for 24 hours and repeat as necc.
It took me several days as I remember, and I rotated the end I poured the Coke down but it eventually loosened the gunk and I was able to knock the batteries out by tamping the open end down onto a piece of wood. This was at least 9 years ago, and that light is working great still.