Tail lights don't work

Was driving car. Was told Tailights were not on but brake lights did work. Parked car. Checked fuse for taillights and it was good. Started car and noticed the IPC was not lighting up. Also the radio does not work, No power, and when I try to shift from park to any other gear (automatic) it will not shift unless I use the shift interlock button next to the lever. It runs fine but I have no power steering. At this point all fuses look good, I found this Toyota TSB on All-data SB#253118 Action #10028225. Basically it says to replace ING1 Relay due to failure in sub-freezing weather. I am a mechanic and have been for 5 years with some ASE's but I work on Chevys and wiring in a toyota appears to work differently to me. Well the schematics are different. It is my parents car I am on my way this morning to drive 2 hrs and try and fix it or atleast diag it. I have a generic OBD2 reader and my trusty fluke and test light. If you can think of a good starting point I would love to hear it. I am working under the assumption this is all tied together. I was going to see what all these circuits have in common and start there, I am going to check the circuits for 12 volts and ground but unless I have something wrong with my 12 or ground I am not sure what to do next.I have so many failures IPC, Radio, Taillights, Shifting, Power Steering. There must be something they all share. Or maybe I will find a rat that needed to make a nest.I have seen that before. Lol