Thanks alot ! Yes, I looked on the back of the radio and I do see the heat sink. Being that I changed out head units and had the exact same problem I'm going to look at speakers then. The more I've researched, the more common I'm finding these speakers do fail often. Interesting. One more question, I can't find any posts on fixing the driver seat. I've gone through numerous junk yards and found that most LS400 seats are similar to mine which is the springs have either colapsed or something. I know something is wrong with the seat and it didn't come from the factory like this. Can anyone give me any recommendation how to fix this?