stupid question but have you tried just turning it on on the front of the player stupid as this sound it may have the ignition live wired into your permanent live feed so the ignition wont do nothing when you switch it on?
also have you checked the earth connection to the iso using a multi meter with a continuity tester?
also some players have a fuse built in just above the iso socket?? worth a try!
ah fook it i was trying not to say anything but i used to fit all this stuff as a living for years and was trying not to bother with it anymore lol
so i can do it all for ya or with ya if ya want buh plus i dont mind fitting any other stuff you want doing if you fancy a trip over to mine up to you mate
i'll stick the kettle on and we can get to work lol
