2007 Camry Dashboard and AC Issues—Need Help Diagnosing

I drive a 2007 Toyota Camry LE. The dashboard, especially the speedometer, intermittently fails. When the dashboard isn’t working, the AC blows warm air. If the dashboard works, the AC blows cold air just fine.

During winter, I noticed the opposite with the heat: it only blows hot when the dashboard fails. I suspect an electrical issue but need guidance on narrowing it down.

Has anyone dealt with similar issues? What’s the most likely culprit, and is any of this DIY-friendly?