The NMU is triggered by a wide-open-throttle (WOT) switch. Since Hemi engines don't have a conventional throttle position sensor (TPS) setup, we picked up voltage from the pedal position sensor (PPS). T-tap the wiring into the #5 pin on the harness located under the battery tray. To keep from running large amounts of voltage through the NSC, we installed 40-amp relays for both the Zex NMU and the purge, and mounted these on the airbox. Route the remainder of the wires from the NSC and the fused 12V power source for the heater under the wiper cowl and back to the bed alongside the fuel and nitrous lines. Install per Dynotune's clear instructions. Be sure to loom the wires for protection and zip-tie in place under the truck.