Somthing is not working right in my setup

for some reson when my subs hit (2x 12W3's) the voltage in the back would drop and then amp (JL 500/1) would turn off and then back on.???? i also have a 300Watt amp hooked up to all this for my speakers and a Cap???? im not sure but i think it could my Cap that went bad??? any other ideas???? (the dash lights in my car deim just a little when the subs hit hard, but it did not be for/..) cap is 1.5uF

Many amps will shut down when the vehicle's voltage drops too low.  Sounds to me like your system is too large for your vehicle and you need a high output alternator.Support the12volt.com

hummm i see what your saying and it make sence but i have been run this same sytem from some time now with no problems.?? can caps go bad???

caps DO go bad....just like a battery

but the light on the cap when i got it it use to go off but now it just stays on all the time.. donsnt it go off when the cap is fully charded and i had porblems with the remote on the cap it would not turn off and so i killed my battery...

Remove the cap from the system.  See what happens.Support the12volt.com

lol it is the same with the cap and with out the cap......so it comes down to me buying a new cap and one have any ideas on a good cap...not to expencive and some were around 1.5F??

The cap is NOT the issue, you car's electrical system is. As mentioned above by DYohn, a highout put alternator is in your future. 

how is mu electrical system the proble when i had it set up befor with i got every thing brand new and it worked just fine for like 6 mouths and all of a suden my cap starts to do weird things and when i have it on or off it makes no differents a problem with my electrical system>>>????? the voltage just jumps between 13-11.4 volts and i know my alternator is just fine because it has supported the system for some time,i even had some one else take a look at it. any way when i hooked it up the first time my system with out a cap my lights would dim and when i put one on it did not dum and all of a sudden the light on the cap wont turn off that signifies that the cap is full and my lights start to dim...

the voltage really drops only when the subs really hit but right after it jumps up to 13+ volts...so a cap fixes this right?>???