what wires are you talking about? the dc panel mount cabling? did you customize the usb to another jack configuration or something like that? i thought even with the passthrough connected you were successfully getting voltage to the adapter, but just not beyond that point. is this correct?
if the voltage looks good at the adapter but neither avs or an atty will fire, i would think one of two things could be the issue, because in theory you should have isolated the problem to the adapter up, including the avs. so for starters, it could be a loosely connected atty in the avs or a dead atty altogether. second, it could be an issue with the atty making the connection with the adapter. the first thing is easy enough to remedy, but the second you'll want to disassemble, clean thoroughly especially the threads, atty connector and adapter contacts, reassemble tightly, by hand, and give it a go again. i've had things get a little loose from time to time and trouble the connections, and i've also needed to clean everything thoroughly to make sure when i reassembled that i made the cleanest and best possible connections between all contact points. i'm hoping this is the issue for you as well, because voltage at the adapter should imply that the atty is getting it and the avs would just be secondary in this scenario.