2003 malibu stereo installation problem

i have a 2003 malibu and i am putting a new stereo into it. the wires are all connected properly now except the accessory wire coming from the car is not sending out power, which is causing the stereo to not shut off and work properly. we tested it with a meter and there isn't any power coming from it. what should i do and how can i fix it? and what is causing there to be no power

i have a 2003 malibu and i am putting a new stereo into it. the wires are all connected properly now except the accessory wire coming from the car is not sending out power, which is causing the stereo to not shut off and work properly. we tested it with a meter and there isn't any power coming from it. what should i do and how can i fix it? and what is causing there to be no power
Does your 2003 malibu have the stock stereo with the oil life monitor and other info built in the radio? If so you might need a certain harness. Otherwise it sounds like you have your constant power wire hooked up to the wrong wire. I think the constant is either orange or yellow.