So I've gotten my JBL80.4 installed - runs two 5 1/4 components in front and a 12" pioneer sub in bridged rear. It worked great for about 2 weeks, then yesterday it would just shut off and I would be left with my two rear speakers. Then, maybe 20-30 seconds later it would fire back up and play for another half hour or so then repeat the process (4 hour drive). What could be causing this? There is no remote turn on wire, power is sensed from the speaker level inputs.
Thanks,

is the amp actually totally shutting down, or is it going into protection?

I don't know the difference. I haven't actually gotten out to see what is going on when it shuts down (on interstate highway). I will check next time it happens to see. Also going to re-check my power and ground connections.
Thanks

Your prolly running the amp too hott... I suggest adding maybe 1 inlet fan and outlet fan... a set of 2 small comp fans (about the size of a cracker) would do fine to col that small amp... But thats what its doing... Mine did the same thing before I added fans.

id guess its overheating majorly...and it has auto shut off protection....thats what id guess sinc eyour using it for multiple uses...

The most common reason for an amp shutting down like this is low speaker impedance.
If your Pioneer sub has dual 4ohm voice coils and you have wired them in parallel (2 ohms) and then connected them to the bridged amp it will overheat & shut down. Minimum inpedance for this amp, and most others, in bridged mode should be 4 ohms.

if it isnt a loose wire then it almost has to be either overloading and automatically shutting off(which would be one symptom of incorrect wirring) or overheating and going into protect, in which case a protect light should come on on the amp; if it has one

silver no offense but i dont think that that would cause it...well i cant really say that we need more info but id guess overheating...thats the only thing i have experienced...that or loose/bad wire!

Yes check the wiring, very low OHM'* can kill many amps, especially 4 ways, but it'* a JBL, and they are usually under rated. Just make sure you're doing what you can do, and you have the wires the correct way (series/parallel).

Also check for shorts crossing between wires. The first time I installed a sub/box/amp in my last car, the box'* own Input box (where you hook it up) had a slight cross going thru it,and whenever i would run serious power thru it it would send my amp (JBL) into protection. The light flashed, it clicked when it went into protection mode too. I had to throw in a new one into the box.

we need more info....i can turn my amp on and off and still have music...you know why...

cuz i like SWITCHES!