Chevy & GMC Vans

I have a chevy 2500 express 2012 with the access package . The access package is the rear side panels open up and each panel has a fluorescent strip fixture. These lights don't work, I checked voltage and there is none present at the fixtures. Does anyone know where the fuse is located for these. The dome lights work but not the access panel lights.
Thanks

That info might be a little trickier to find since I don't think GM made a great deal of those contractor vans.

But let me introduce you to two precious gems. Sources for schematics, drawings and service info for your van. If it's anywhere, it'll be here:

https://charm.li/

https://www.gmupfitter.com/body-builder-manuals/