problem

hi, today for the first time i have a problem with my system that i could not firgure out. or atleast not even 50% sure of. ok here it is. on my way to work today i turned off my subs because i was listen to a slow jam song that sucks with to much bass and then i turn the volume up to 54 out of 62 and the amp cuts off and a red light comes on. and i have an apline pdx4 100 for my speakers and on my owners manuel a red light could mean either one of these:Amplifier circuit is abnormal. An electrical short has occurred, or
supply current is too high. or Power supply voltage is too high. or Ambient temperature is too high. and it did not blink but if it would indicate that the output protection mode is on and it is about to overheat. now the amp was hot the first 3 times it went into protection mode the amp was kinda hot but i knew it was from the sun because it was hot from not even using it. and then on the way home the amp was cold becuase it sat for 10 hours and 8 hours of it being in the dark. and on the way home when it would turn red and turned off i started to play with it to make it go into it. find the problem and i was playing with my fader on my head unit and i was not able to get it to stop working when my front speakers where the only one's working but when i tryed it with my back ones i got it to stop work working so i think the problem lie's with channel 3 or 4. and that is about all i know. and i know this is like one big run on sentence. and i did try setting my gains down and it did not help.

slight update: after i did some real world testing on it. ( there isn't a audio shop in my area besides cc to test my amp) i came to found out this info. with my dmm my speakers with the wiring has an ohm of 4.2 for each channel which sounds farley decent for 4 ohm speakers plus the wire impence but the thing i found out most interesting was that i could not get my amp to go into protection mode with no load but with the rca's still connected and that my amp has a speaker inside of it can you have to put your ear to to hear it. but most importantly i found that if you connected anything into channel 4 that after you turn it up to lets say 56 out of 62 then the amp goes into protection mode and if you have 3 speakers plugged in to channels 1-3 then the amp works fine through out the whole volume range but if you take those same speakers and plugged them in the channels in this order 1 2 4 then the amp goes into protection mode. so my thing to say is that channel 4 has a short in it/ is the clipper. now that amp is 1 month old so i should still have a warrenty left but i just want to make sure that is the problem.

I guess it's easier to troubleshoot when you can see it. What happens if you connect the speaker that was on channel 4 to any of the other speaker channels.

it will work fine. any speaker that goes on channel 4 makes the amp go into protection mode but if i swap it with like a speaker from channel 2 the same thing will happen.but btw i heard somewhere on here before i went to work on another digital type amp and they had close to the same problem and they took the fuses out for like 30 mins and it stopped having it. and i tired that and it seemed to work so far i have not been able to get it into protection mode.

hmmm .... that's odd, since it's microprocessor controlled it might have just been a glitch