I had nothing but problems with raptors. First one came on truck FFRP. Second one FFRP fail but warrenty. Third one was relocated down by tank. FAIL....
Turns out the voltage is regulated through the computer. Upon testing the start up voltage was correct but running voltage was low inturn drawing amps frying the pumps. The starting voltage pulses full voltage along with half voltage at first to aid in hydro lock hot start scenario. Once it sees revolution from Crankshaft it turns to full voltage. Try testing your voltage at the lift pump connection with key turned to run and then the key turned to run with a bump to the starter. You sould see a pulse of 12v then a drop to a lower voltage untill the starter is bumpped. If erratic voltage after starter bumpped; the internal cumputer regulated voltage circuit is becoming compromised. Dodge (not Cummins) did some funny things on our year trucks. Regulating the lift pump voltage through the Engine Control Module was one of them. The circuit can become compromised.
I ran my new fuel lift pump on a hot relay triggered directly off ignition eleminating all the fancy mopar electronic crap. Simple, redundant.