KA-t no start electircal problem. please help

[Phantom240sx]

Hey guys im new to posting hope this makes it in the right place. I have a KA-T setup on my 95 240sx. on christmas after i fulled it up with gas the car was sitting idle then suddenlly died as if the key was turned off. My dash lights and idiot lights dont work, my corner lights work but my headlights dont, my stereo doesnt turn on, but my dome light does turn on when door is open, the buzzer goes off when the key is in the iginition in on position and door is open, the horn doesnt work. I had pulled the battery out and had it tested and battery had a full charge. My aftermarket alarm isnt arming right either it flickers my locks and doesnt chirp but the arming light seems to pop on once armed,