🤦🏾my worst nightmare

[Terry Lindsey]

09 Cadillac CTS 3.6
Car stopped on me I coasted to an empty lot at a standstill I tried to start the car nothing no electronics work no power had the car towed home went and bought a brand new battery installed it all accessories come on power windows door locks horn turn signals headlights radio etc all works but when you turn the ignition knob to the third position doesn't start you don't hear the fuel pump prime hum so I jumped the starter relay from pin # 30 to pin# 87 and nothing still didn't start I did more research got a test light test pin #30 and there's no power going to it it's supposed to have constant 12 volt it's dead so I thought the car was in theft mode so I did the 30 minute demobilizer key relearn procedure and still nothing no clicks no fuel pump prime hum so then I found the high-powered fusible link between the alternator power wire and the fuse box power post I changed it out with another one OEM check the continuity after repair and it's good nothing will restrict power then I took the fuse box on loosened it lifted as high as I could get it to look under it to see if anything was out of place or anything look shorted out and nothing then I traced the battery cable from the trunk where the battery is up to the under hood fuse box to the power post and it checked out good is there anything else that I'm missing or if anybody had this problem I appreciate if someone could lead me in the right direction that I can actually get results this car is driving me crazy