Why doesn't my Xbox 360 connect via HDMI

Solution 1:

According to xbox support, you may need to try a reset of your display settings:

• Check the connection for the A/V or HDMI cable on your Xbox console.
• Check the connection for the A/V or HDMI cable on your television.
• Try plugging your HDMI cable into a different HDMI port on your television.

• Reset your display settings. To do this:

  1. Remove any discs from the disc tray.
  2. Turn off the console.

  3. Turn on the console.

     Note If you are using an Xbox 360 Wireless Controller, turn on the console by using the Guide button on the controller. Make sure that you use the player 1 controller when you do this. The player 1 controller will have the upper-left light illuminated.

  4. As the console starts, on the controller, press and hold Y while pulling the right trigger. The display settings are reset to the default settings, and then the console automatically restarts.

Since you say you've done the first points, the display setting reset is all that you haven't tried so cold boot the console and hold Y+RT.

There is also the possibility that your display is having trouble with the resolution that the 360 is using. It seems to want to default to the highest resolution which not all displays support. The quick test is to try it with a display that you know supports 1080p HDMI in and if it works without changing anything, then that seems to be your problem, but it may still be worth it to try changing the resolution on the 360 anyways:

With an HD AV connector (some connectors have a switch on them for HDTV), ensure that the directions are correct, otherwise you are flying blind. With the current dashboard update:

1. Home button.
2. Settings(all the way to the right).
3. Console Settings(down 3,A).
4. Display(A).
5. HDTV settings(A).
6. Try lower resolutions(up and A selects a lower resolution, but since the menu wraps around, I can't be more precise).
7. Set it to the lowest resolution.
8. Power off the console. (if working blind, unnecessary)
9. Switch to the HDMI cable. (if working blind, unnecessary)
10. Power on the console. (if working blind, unnecessary)

11. If that works, go through increasing the resolution setting to find the best resolution that works for your display.

    Note I believe it should keep the setting even though you switch cables after setting it, but if I am wrong, you may have to go back and check if it lost your settings, meaning you'll have to do this blind with the HDMI plugged in. You could do this blind to begin with to avoid this extra concern, but I find mistakes are more likely when you can't see.

Make sure to test it thoroughly before writing off a solution. Sometimes Xbox 360 takes a little bit of time as it starts up before it outputs to the screen.