Just a FYI that may be of help.
I recently lost one of the two bulbs in my galley light. It is a 36" fixture with two tubes and ballasts. When I checked for 12 volt supply I found out that the ballast was the problem and not the tube. I confirmed by switching the good tube for the one that was inop and the good one didn't work as well.
When I checked with Winnebago, all they could offer me was an new lamp to the tune of $80.00 and the ballast was not avail as a separate item.
After a little research I found out that the lamp was made by Thin Light and I could order the ballast from a parts dealer at a cost of about $27.00.
Ballast # IB-P147
Part Supplier
www.charment.com
I spoke with Mile and he was very helpful.
I hope that this may be of help to someone.
Pete