Pat covers what he did to his Oasis in his article and video about his first year with his 18BH model. One item was to replace his interior lights with Optronics brand lighting. It is a very informative read/view.
Pat is a member of this forum, too.
Look for the January 24th 2017 article:
The Small Trailer Enthusiast | News & info for the small trailer enthusiast
I hope this helps with your model. Luckily, I have the same 18BH.