RepairPal Certified shops can diagnose and repair your 2015 Chevrolet Express 3500. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Check over all fuses and main connection to the fuse box. Just replacing the fuel pump would not directly cause this issue. Hands in inspection is needed but trace back all of your steps.
Alex
Highly recommend seeking out *hands-on* help from qualified personnel.