urgent need help

[impala4looks]

ok here is the deal I went to put a system in my 2002 this morning (I have a stock radio I’m using a line out converter, if that makes a difference)anyway I go to start the car but the only thing that happened was my cluster went on it lit up and showed me how much gas I had and the message center was on but my voltage wasn’t showing anything I couldn’t lock or unlock my doors (using the power lock) also I couldn’t unlock my trunk keep in mind my car is in ACC at this point also I could put it in gear without pushing in the brake. I have no clue what this could be I checked all fuses and they were ok.i also checked the codes and nothing showed up.and yes the battery is fully charged.