I have a 2004 Hyundai Elantra and am trying to install a stereo but dont know what the wiring diagram is..any help?

TRY HERE

https://workshop-manuals.com/hyundai

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2004 Hyundai XG350 Car Stereo Radio Wiring Diagram
Car Radio Constant 12v+ Wire: Red
Car Radio Switched 12v+ Wire: White/Green
Car Radio Ground Wire: Black
Car Radio Illumination Wire: Brown/White
Car Stereo Dimmer Wire: Green
Left Front Speaker Positive Wire (+): Brown/White
Left Front Speaker Negative Wire (-): Black/White
Right Front Speaker Positive Wire (+): Brown/Yellow
Right Front Speaker Negative Wire (-): Black/Yellow
Left Rear Speaker Positive Wire (+): Brown/Red
Left Rear Speaker Negative Wire (-): Black/Red
Right Rear Speaker Positive Wire (+): Brown/White
Right Rear Speaker Negative Wire (-): Black/White

. Hope it solves you problem. Car Stereo Radio Wiring Diagram 2004 Hyundai Elantra

2000 Hyundai Elantra Car Stereo Radio Wiring Diagram
Car Radio Constant 12V+ Wire: Light Green
Car Radio Ignition Switched 12V+ Wire: Brown
Car Radio Ground Wire: Black
Car Stereo Illumination Wire: Dark Green/White
Car Stereo Dimmer Wire: Dark Green/Black
Car Stereo Antenna Trigger Wire: N/A
Car Stereo Amplifier Trigger Wire: N/A
Front Speakers Size: 5 1/4? Speakers
Front Speakers Location: Doors
Left Front Speaker Wire (+): Green/Red
Left Front Speaker Wire (-): Light Green/White
Right Front Speaker Wire (+): Red/Blue
Right Front Speaker Wire (-): Light Green/Black
Rear Speakers Size: 6? x 9? Speakers
Rear Speakers Location: Rear Deck
Left Rear Speaker Wire (+): Yellow/White
Left Rear Speaker Wire (-): Yellow/Blue
Right Rear Speaker Wire (+): Green
Right Rear Speaker Wire (-): Green/Blue

http://www.modifiedlife.com/2000-hyundai-elantra-car-radio-stereo-wiring-diagram/

try that

1998 Hyundai Elantra Car Stereo Radio Wiring Diagram
Car Radio Constant 12V+ Wire: Light Green
Car Radio Ignition Switched 12V+ Wire: Brown
Car Radio Ground Wire: Black
Car Stereo Illumination Wire: Dark Green/White
Car Stereo Dimmer Wire: Dark Green/Black
Car Stereo Antenna Trigger Wire: N/A
Car Stereo Amplifier Trigger Wire: N/A
Front Speakers Size: 5 1/4′
Front Speakers Location: Doors
Left Front Speaker Wire (+): Green/Red
Left Front Speaker Wire (-): Light Green/White
Right Front Speaker Wire (+): Red/Blue
Right Front Speaker Wire (-): Light Green/Black
Rear Speakers Size: 6′ x 9′
Rear Speakers Location: Rear Deck
Left Rear Speaker Wire (+): Yellow/White
Left Rear Speaker Wire (-): Yellow/Blue
Right Rear Speaker Wire (+): Green
Right Rear Speaker Wire (-): Green/Blue

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Go to www.hmaservice.com and register( Vehicle by VIN). Afterward, you have access to shop manuals, service bulletins, wiring diagrams, etc. about your vehicle.

repair manuals have wiring diagrams
1996 2013 Hyundai Elantra Haynes Repair Manual PDF