hold old is the headunit? i havnt ever had a headunit just straight up die on me before, and i’m on my fourth. The only reasons i’ve had for changing them is their ability to play certain cds seemed to decrease after awhile. If the quality of the unit isnt too good and its got some years on it i would just assume that it just quit on you.
If it has power going to it then it should turn on. Did you check all three power wires? make sure your checking BOTH the constant AND the accessory power wires. also remember to check the ground with a meter. If all checks out okay…then i would assume its dead.
selling the car would certainly fix your problem haha