How do i wire a line out converter?

Ok I'm about to give up.... I'm tring to install an aftermarket amp and sub in a 2003 deville with a factory head unit. I wired in the line out converter as the diagram showed but the sub will play sometimes and sometimes not. I thought it might have been a faulty loc so I exchanged it for a new one but no change there. Also the remote wire on the amp kit... I'm having an issuse with it as well. I only get a signal when the car is running not when the key is just on. Can someone please help. Lol