Trailer Dome Lights - GMC Denali

[72-SS-L48]

Hi All,

Since purchasing our '98 Wells Cargo Autowagon, we have not had trailer interior dome lights. All exterior lights work just fine. We always thought it was something trailer related until a friend hooked up his truck to the trailer and sure enough the inside lights work.

Now we're thinking it's two vehicle related (we have a 2012 GMC Denali). All fuses look good. Even replaced a few just to be safe.

What else could it be? Anyone have similar problems?

Thanks,
Dave