hm, ok. gonna have to remove the passenger seat to get to the amp while it's still hooked up. I'll try JBjorgan's advice to test. I'm afraid that the audio wires will be in a harness like they are on this end, so is it sensible to solder a needle or paperclip onto a wire and jam that into the back of the ground pin's socket, for testing?

i'm trying my hardest to make sure each step is properly tested. I don't want to miss whatever it is

I'm not really electrically inclined (software guy) so bare with me here: To check this with a multimeter does the + of the multimeter go to the + of the device and the - to somewhere on its ground wire or ground point (of the device) to test? what do i look for? a deviation from 12v ?

Sorry to have so many questions, hope that's readable