you've got more problems than a minor diesel soak of the wiring
analyze and find the real problem.
Dodge Ram 2500 5.9 Blow-By - YouTube
Dodge Ram 2500 Cummins 5.9 blow-by - YouTube
plan on driving the Chev. until you find the problem unless you have an extra $12,000 to spend on a new Cummins crate engine.
just brush some soapy water on the wiring harness and lightly mist spray off. no hard stream or power washer. then pull the connectors apart, spray with electrical contact cleaner and then coat with silicone dielectric grease. NO substitutes especially NO WD-40. The wiring diesel soak is not the cause of all your engine problems.
sounds like you just bought someone else's throwaway trouble that was not treated and maintained by the prior owner.
"""is there any other solutions?"""
sell it to some other sucker if you don't want the problem of fixing the engine correctly.
Cummins are like a good woman, gotta take care of it and treat it right or you're not gettin' any tonite and for awhile to come.
Burning used motor oil in a HPCR Cummins is like having sex with a blow up plastic doll. Ruins a great engine and ruins a man.