i just bought a 03 sc430(i love this car) any way im taking my first hi-way drive,and the sub (that wasnt workin when i bought the car ) starts working!!! Then after a few hours and mile it stops!
so i pull up the rear seat cushion and find two rca cables two other wires and a power cord that is hooked to the battery

sound guru's please help

 

Do the wires go into the trunk where the amp is installed? Did your 03 come with the OEM stereo (ML) head unit, or is it aftermarket?

 

the headunit and nav are bone stock!!

 

You need to verify where the wires terminate. Sounds like you're the type of person who's not afraid to do a little troubleshooting. Do some more digging and get back to us.

 

...sounds like the previous owner may have added another amp & possibly sub, but took it out before selling. The sub in there now may have a voice coil wire thats damaged & this could be the reason it played awhile then stopped. Might be able to push on it, to get it playing again. If this is indeed your issue, you might want to replace it or have a stereo shop look at it. Some guys have done the foam repair kits, but i don't think thats your issue..

 

Also do the obvious: Check the connections from the sub to the amp - maybe something wasn't plugged in tight when the previous owner returned everything to stock.