Yamaha HTR-5920 Problem

I got the Yamaha HTR-5920 from a friend. It came with 6 of the original speakers plus the subwoofer. Him and I hooked up all the speakers and the sub. The speakers work fine. But the Subwoofer is extremely low. I can barely hear it at all. I know the sub works because we connected it to my friends car system and it worked much louder than when it was connected to my reciever. I have the speaker level for the sub maxxed out as far as I can tell (+10 db). I think the problem has something to do with the settings because on the front panel only the "L" and the "R" are lit up and I have 6 speakers plugged into it not just left and right. So either theres a problem or its always like that. When you look at the front panel you can see right next to the "L" and the "R" that there are indicator lights for the sub, surround, and center but I have never seen them lit up. Someone help please! You can either message me on AIM or reply here ill be on both. Thanks!