My 04 T winds had light problems, turned out to be ground problem. A quick test is to run a ground wire (negative side) from the house or chassis batteries to the fan shroud with an aligator clip if it works you have ground issues.
The tech who sorted this out for me explained that there is a great deal of fiberglass/plastics on front caps and not a lot of metal, ground failure is a common problem.
If this doesn't work I agree it's back to fuses which should be under the drivers feet in the outside access panel. These are labeled at least they were on my coach.
Good Luck