If you checked the bulb( I'm assuming you did though you didn't say) then its either the socket or the wiring. It could be related to the speaker if both problems started at the same time. If you have a multimeter or a test light you can check this stuff. I would check to make sure the socket has good continuity to the battery ground first. Then work my way from the socket towards the fuses checking the wires for continuity. If its related to the speaker, then you would have continuity from the speaker wires to the socket or something similar to that, showing you have a short to power. The closest those wires get to each other would be under the dash, or at the fuse box I beleive.