2003 trailblazer cd player

ok thinks for all the help with takin the radio out . now i have hook up a new one put when i turn the park lighs on the radio turns on . i hook up the yellow wire by its self i hook up the red wire but the only way it cut on was when i hook up the orange in white wire to the red . also when i unplug the radio there was two plug to hook up put only one hook up to the wire harnesses

Your original radio is a Class II data unit. It turns on and off through data messages sent from the vehicle's body computer. You shouldn't just remove the factory radio and discard it. You either need a radio relocate kit to still keep the factory radio in the data circuit or purchase a radio delete kit. Most kits come with clear instructions and new plugs to allow you to simply wire in an aftermarket radio. They also give you a switched power lead to turn on your new radio. There are different kits available for different vehicle options. These methods retain the chimes and prevent you from doing serious damage to your truck. At least buy a wiring kit for your truck. You will still have to wire in an ignition circuit for the radio but it will make your install job better and easier.

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sparky