The factory upfitter switches in your 2019 Ram 2500 provide pre-wired circuits for accessories like work lights, winches, and custom equipment. When these switches fail to provide power or stop functioning, diagnosing the auxiliary switch circuits helps identify whether switches, wiring, fuses, or the control module has failed.
Upfitter Switch System Overview
Ram's upfitter switch package includes dash-mounted switches connected to dedicated high-current circuits. Each circuit has power and ground wires routed to the engine compartment for easy accessory connection. A body control module monitors switch inputs and controls relay outputs. The system provides organized, fuse-protected power without aftermarket wiring modifications.
Switch Input Failures
The rocker switches on the dashboard can fail mechanically or electrically. Internal contact wear prevents signal transmission to the body control module. Illumination may work while the switch function fails, or the entire switch may be non-responsive. Test by checking if the BCM receives the switch input using diagnostic equipment.
Fuse and Relay Circuit Problems
Each upfitter circuit passes through dedicated fuses in the engine compartment fuse box. Blown fuses from accessory overload, short circuits, or water intrusion stop power delivery. Relays controlled by the BCM switch high-current loads—failed relays prevent power regardless of switch function. Check fuse box labels for upfitter circuit fuse locations.
Wiring and Connection Issues
The upfitter wiring terminates in the engine compartment for accessory connection. Improper installation, corroded connections, or damaged wires cause circuit failures. Ground connections are as critical as power—poor grounds prevent accessory operation even with proper power supply. Inspect all connection points for corrosion or damage.
Code B1E16 and Module Communication
Code B1E16 relates to auxiliary switch circuit or control module faults. The body control module processes switch inputs and controls output circuits. Module failures can disable upfitter function entirely or affect individual circuits. Programming issues after module replacement require dealer configuration.
Accessory Load Considerations
Accessories exceeding circuit capacity blow fuses or trigger protection features. Verify accessory current draw matches circuit ratings. Some high-power accessories require modifications beyond factory upfitter capacity. LED work lights and similar accessories typically work well within factory specifications.