If your display is showing nothing with the Aluminum Type-C to HDMI Cable, the most common cause is which USB-C port you plugged into. The Type-C end of the Aluminum Type-C to HDMI Cable needs to go into a Thunderbolt 3 or USB-C port that carries video, not a charging-only port, and it supports resolutions up to 4K at 60Hz.

How to fix display problems with the Aluminum Type-C to HDMI Cable

1. Plug the Type-C end into your device's Thunderbolt 3 or USB-C data port, not the charging port. A charging-only port will not carry video.
2. Plug the HDMI end directly into your monitor or TV.
3. Switch your monitor or TV to the HDMI input you actually plugged into.
4. Detect the display on your computer. On a Mac, open System Settings and go to Displays. On Windows, open Settings, go to System, then Display, and select Detect.
5. Try a different USB-C or Thunderbolt port on your device.
6. Reseat both ends of the Aluminum Type-C to HDMI Cable, and check the connectors for bent pins or debris.
7. Set the right expectation on resolution. The maximum the Aluminum Type-C to HDMI Cable handles is 4K at 60Hz.
8. If you are displaying from a smartphone, expect a lower resolution. Output from a phone may be limited to WQHD rather than 4K.
9. If you are running the cable through a hub, use a Thunderbolt 3 port on that hub. A USB-C port that only does pass-through charging will not send video.
10. Test the same monitor with a different cable, or the Aluminum Type-C to HDMI Cable with a different monitor, to work out whether the cable, the source, or the display is the problem.
11. Check what you are connecting. The Aluminum Type-C to HDMI Cable is not compatible with the Nintendo Switch.