I had the same problem on my 240D and replaced all the lights and rheostat. If possible, I would recommend jumping the contacts on the rheostat (as suggested above.) It's not worth buying a new rheostat because the lights (even with new bulbs) are so dim that you will never have them set any lower than high. Try jumping it and see if any of the lights work. If some do, then just replace the non-functional ones and save the $36 for a rheostat.