Is there any stereo wiring diagrams or codes online

Check this for 1995 Cadillac Deville Car Stereo Wiring Schematic:

Car Radio Battery Constant 12v+ Wire: OrangeCar Radio Accessory Switched 12v+ Wire: YellowCar Radio Ground Wire: BlackCar Radio Illumination Wire: GrayCar Stereo Dimmer Wire: BrownCar Stereo Antenna Trigger Wire: PinkCar Stereo Amp Trigger Wire: N/ACar Stereo Amplifier Location: N/ACar Audio Front Speakers Size: 5 1/4" SpeakersCar Audio Front Speakers Location: DoorsLeft Front Speaker Positive Wire (+): TanLeft Front Speaker Negative Wire (-): GrayRight Front Speaker Positive Wire (+): Light GreenRight Front Speaker Negative Wire (-): Dark GreenCar Audio Rear Speakers Size: 6" x 9" SpeakersCar Audio Rear Speakers Location: Rear DeckLeft Rear Speaker Positive Wire (+): BrownLeft Rear Speaker Negative Wire (-): YellowRight Rear Speaker Positive Wire (+): Dark BlueRight Rear Speaker Negative Wire (-): Light Blue

Hope this helps.