Trying to get the original radio functioning. I know really nothing about wiring but here's what's happening. The radio does have power but the sound is barely heard. I can scroll through stations but the sound is very low. Oh yeah and there is no speaker on it so the sound is coming from the radio it's self. I installed a speaker but nothing changed. There are two wires for the speaker and an extra green wire all not attached. Any thoughts on what's going on ?