Update: I disconnected the ignition button and shorted terminal 1 and 4 on the harness side to mimic the push button PUSH action, the car behaves exactly the same. I also switched the push button with the one from my Maxima which is exactly the same as the one from the Infiniti but the problems continues so I don't think the push button switch is the problem. One thing I notice is the fan blower motor also shut off when the car automatically switched from ACC to LOCK . The instrument panel, AV, A/C, blower fan, and the screen all turned off regardless if the engine was running or not. The only difference is if the car is running, the engine won't shut-off whether it was in park or when I was driving it. The car drives just fine without any engine issues, no loss power or stalled. I traced the circuitry and it looks like both the ACC and Blower fan relay coils are fed by the same power line coming out of the PDU. I checked continuity between the PDU harness and the harness at the fuse block and everything checked out. There is also voltage at the PDU terminal that fed the relays' coils so I am at a total loss on what's going on. I went through the Infiniti PG FSM as far as measuring the voltages and continuity and everything seems fine. I also took the car to the shops and auto parts stores to read fault codes and no codes were present. The shops had no idea and recommend I get some one with electrical expertise to troubleshoot. I am an electrical engineer with 30+ years experience in power distributions on low, high, and extra high voltages but that doesn't help. I talked with the Infiniti dealer and they wanted to charge around $250.00 just to hook up their diagnostic tool and see what they can find. I am sure they will "recommend" replacing every modules one by one until everything in the car is new and hopefully the problems will go away. Dealer and service shops don't really troubleshoot anything any more; they are just parts swappers. Please let me know if there are anything else I could check. I have other cars to use so this one will be sitting in the garage until I can figure out what's wrong with it. It's a personal challenge for me now. I truly appreciate any help or pointer.