Audio amplifier sound comes and goes / inconsistent (2013 Gen 3)

Similar to others here, I have a 2013 Gen 3 in which the amplifier under the passenger seat inconsistent stops working / cuts out.

Most of the time I can get it working again by unplugging and replugging its power connector, but sometimes this doesn't work. (Note: when I do this, I can hear the speakers gently "pop", so power is definitely being fed from the amp to the speakers.)

So I presume there is a wiring, circuit, or heat issue somewhere, either in the amp or the speakers.

Does anyone have any tips on how to diagnose the problem? Other than getting a used amp here or on eBay...

Thanks!

 

Amp model number is 86280-0WA51. Pictures attached.

JBL Amplifier 86280-0WA51 no 1 by ttzprius posted Sep 20, 2021 at 11:30 AM

JBL Amplifier 86280-0WA51 no 2 by ttzprius posted Sep 20, 2021 at 11:30 AM

JBL Amplifier 86280-0WA51 no 3 by ttzprius posted Sep 20, 2021 at 11:30 AM

 

Same problem as this post (2015 Prius 4 No Audio Output | PriusChat)

• No sound
• Pressing the volume controls on the steering wheel or twisting the knob no longer displays anything on the head unit (HU)
• Neither the voice activation button nor the head unit buttons create a beeping noise
• B15D3 and B15C3 errors
• When I DO get the amp working (by unplugging and replugging it), it will often cut out if the volume is too high

 

For others, here are some links regarding the B15C3 and B15D3 errors:

• I can't post links yet, but do a Google search for "toyota B15D3" and pick the tovenza links