Unfortunately, no, thereís no way to check on the status of the amp or the amp mounted fuse without full commitment. My sub wasnít sounding like it was working a few weeks ago and I ended up taking out the back seat. Itís not that bad to do, just takes a while, especially if itís your first time. You can see just how much needs to be removed to find the amp in my before and after photos below. Once you get it apart, thereís an LED on the top of the amp that should glow green when the amp should be working. It will switch to blinking red if itís in some sort of protection mode and just be off if the amp has no power or a blown fuse.
I say if you donít like your head unit, replace it for that fact alone. I just finished installing my new head unit yesterday and I performed the install myself. Keep in mind, I know next to nothing about electronics and I got the head unit swapped without any issues. For reference, my car had the Pioneer AVIC-X940BT and I now have the Pioneer AVIC-W8400NEX. I swapped because the sound quality was junk when playing audio through an iPod and now my new head unit has wireless Apple CarPlay.
Check your amp for the status light, but swap the head unit either way. Youíll be happy you did.
2013 Evora IPS - Carbon Gray
2016 BMW 328xi - Estoril Blue