How can you test if a capcitor still works or not?

also, what do you think my problem is? is it cause of my soundsystem?

well when i turn my car off, and if i try to turn it back on again a few minutes after i just turned the car off, i got a whining belt noise. it also happens if i listen to the radio with the car off, and when i turn it on i get the whining noise again. i was thinking that my alternator belt might not be tight, but it seems like its the correct tension. also, when my car is running fine, theres like a whistling noise in the engine bay.
oh, for my system, i have two 12" Rockford Punch HX2's, and using an 700.2 amp thats bridged.

thanks in advance for the people who try to help.

 

charge it, leave it for an hour, check voltage
it should hold the charge

 

what do you mean charge it? like run the car? and get a meter and then check the cap?

 

use a digital volt meter across the top of the cap after turning the car on. if it has a good reading, then you'll know it still works... you could also touch it to your tongue like a 9v battery... but please don't have your family come to me when you die of electrocution.... haha


Evan

 

i like the tongue idea!!! lol

 

umm, okay, my tounge hurts. thanks guys....but really though, does anybody have any kind of idea of why my belts or something is squealing even though the belt looks fine, and the tension is fine? doesnt sould like i have a problem with the alternator since my car has no problems staying on when the car starts fine with out the squeal.