Dodge 2015 RAM Owner's Manual page 267

STARTING AND OPERATING 265
1. Remove cap from DEF tank (located on drivers side of
the vehicle or in fuel door).
4
DEF Filler Cap And Fuel Fill 1500/2500/3500 Models
1 — Diesel Exhaust Fluid Fill Location
DEF Filler Cap Chassis Cab Models
2 — Diesel Fuel Fill Location