While I was driving, my JBL sound system went out. Now only the front speakers seem to have any volume at all. The rear speakers are barely working. I checked the rear speakers by hooking them to an external sound source and they work great. I checked all of the fuses along the underside of the rear deck. They are all good. I'm guessing this JBL sound system uses some kind of rear amplifier. Would this be the unit back there that the antenna cable is connected to? If so, it must be getting some power or my radio wouldn't work. Is there somthing I should check?

The Amp in the trunk might have blown,
Town Car Radio Wire Diagram
Car Radio Battery Constant 12v+ Wire: Pink/Light Blue
Car Radio Accessory Switched 12v+ Wire: Yellow/Black
Car Radio Ground Wire: Black/Light Green
Car Radio Illumination Wire: Light Blue/Red
Car Stereo Dimmer Wire: Blue/Red
Car Stereo Antenna Trigger Wire: Blue
Car Stereo Amplifier Location: Trunk
Car Audio Front Speakers Size: 5? x 7? Speakers
Car Audio Front Speakers Location: Doors
Left Front Speaker Positive Wire (+): Orange/Light Green
Left Front Speaker Negative Wire (-): Light Blue/White
Right Front Speaker Positive Wire (+): White/Light Green
Right Front Speaker Negative Wire (-): Dark Green/Orange
Car Audio Rear Speakers Size: 6? x 9? Speakers[img src="http://www.assoc-amazon.com/e/ir?t=modilife-20&l=as2&o=1&a=B00009UHRE" width="1" height="1" border="0" alt="">
Car Audio Rear Speakers Location: Rear Deck
Left Rear Speaker Positive Wire (+): Gray/Light Blue
Left Rear Speaker Negative Wire (-): Tan/Yellow
Right Rear Speaker Positive Wire (+): Orange/Red
Right Rear Speaker Negative Wire (-): Brown/Pink
Check the fuses

first off stock wiring for speakers,and or amp are with minimal wiring.Rewire system for better sound quality,also use noise suppresors if needed.

look under back seat for preamp

That, my friend, is in your balance system of the radio itself. Check it with other speakers you know are good. You'll see what I mean.

Radio Constant 12V+ Wire: Blue/Yellow
Radio Switched 12V+ Wire: Gray
Radio Ground Wire: Brown
Radio Illumination Wire: Dark Green
Dimmer Wire: White/Green
Antenna Trigger Wire: None
Front Speaker Size: 6 1/2′
Front Speaker Location: Doors
Left Front Speaker Wire (+): Pink
Left Front Speaker Wire (-): Purple
Right Front Speaker Wire (+): Green
Right Front Speaker Wire (-): Blue
Rear Speaker Size: 6′ x 9′
Rear Speaker Location: Rear Deck
Left Rear Speaker Wire (+): Black
Left Rear Speaker Wire (-): Yellow
Right Rear Speaker Wire (+): Red
Right Rear Speaker Wire (-): White

pls rate

Thermal issue is shutting down amps till temps moderate. You must be driving your system too hard. And check out your tone control settings especially the bass. Every 3 db boost forces amp to double power at that frequency so if you are already blasting at 100 watts, a 3 db boost will compel amp to put out 200 watts, etc. Very easy to overdrive and overheat amp. You might want to try blowing air over output stages to improve cooling at high volume levels.

You are lucky that you have good protection circuits - otherwise by now you would have blown the output stages.

Well the voice coils in the speakers may be fried, or on their way out. Has anyone been simply turning it up too loud, or too bassy, or at obscene levels.

sounds like you got a bad stereo. it happens. i've i had the same thing happen, but the volume went up instead of down. check all the wires and make SURE they are all hooked up right.

sounds like a speaker problem, but it could be the stereo itself. it could have a damaged circuit board. the only way to find is to test the speakers/head unit.