In car sound system button stuck on Volume Up

The device in question is a Sony sound system for my vehicle. Model: CDX-CA900.

I’m having trouble turning it on anymore. At first I thought that the Source button (turns it on, it only has a few buttons) might be faulty. So I troubleshooted and reset the whole thing, and even did a continuity test on the button. Seems to work, but when I force it to work by putting a CD in to turn the system on, the volume goes up to maximum. I had a moment to put two and two together, and decided to do another continuity test on the volume up button to find it is permanently stuck on. At this point I’m assuming that is the reason I can’t turn the system on.

Any suggestions for a fix?

I’m seriously considering just soldering off the button and using the remote(s) instead.

On the very right of the bottom part is the Off button.

Left middle button is Source. Top button is Volume Up. Bottom button is Volume Down.