Just a question...do you have an amp powering the highs as well? The reason I ask is because if you do and depending on how you have everything hooked up you could have either a bad preout on the deck or a bad rca. If you don't have the highs amplified through an external amp and the sound comes through the left side for the subs as well as the highs, my suggestion would be just to get a new deck. I hope I explained that how I wanted to instead of tongue tying myself through my response.