Hello!

I was helping a friend install a subwoofer in his 2003 XC70 Wagon. It's a powered sub that has both low level and speaker level inputs. Since I doubted (correctly?) that the stock radio had low-level RCA outputs, I opted for the simpler solution which, acording to the instructions that came with the sub, was to split the speaker wires going to a pair of speakers (in this case, the rear door speakers) and send one set to the door speakers and one set to the speaker-level inputs on the sub. We did this, powered up the sub and it worked really well. . . .for about 5 minutes. Then the little tweeters all that way in the back started to sound like the bass was distorting, then the same thing happened to the rear door speakers, then both sets of speakers stopped working altogether. Now, only the front speakers are working. We checked the fuses that we could find in the front panel by the drivers door ~ there seemed to be 3 that were related to the audio system and all were fine. I double-checked my wiring job at the splits to make sure no wires were touching, grounding out, etc. and they were fine. My guess is that either there's a fuse that's blown that I haven't found, or there's an amp somewhere that's shot. I don't know if this car has separate amps for the front and rear speakers or if the amp(s) are located inside the head unit? Any help on where to look next to fix this is much appreciated ~ thanks!