If your Switch Dock has no HDMI signal, start by checking the HDMI connections. Ensure the HDMI cable is plugged firmly into the dock’s HDMI OUT port and the TV’s HDMI IN port. Try a different HDMI cable—use the official Nintendo cable, as third-party cables may be faulty. Test a different TV input (e.g., HDMI 2 instead of HDMI 1) to rule out a bad port. Check the dock’s power supply: use the official Nintendo adapter, ensure it’s plugged into a working outlet, and look for the dock’s power light (orange or green). Power cycle the dock and TV: unplug both for 30 seconds, then plug them back in. Update your Switch’s system firmware to the latest version, as outdated software can cause HDMI issues. If the signal is still missing, the dock’s HDMI chip may be faulty—contact Nintendo Support for repair.