Car Stereos: amp, digital multimeter, ac volts

Question
why is my amp not working i re wired it and still aint working the speakers are thou?

Answer
Hi,

I'd need a lot more detail on your problem before I could give you any kind of meaningful answer.  

In general, if you're trying to do any troubleshooting in a car audio system, you'll need to have a digital multimeter available.  Without this tool, all you can do is guess.

You can set the meter for DC volts and test the voltage present at the amp's power terminals.  You should see 12 volts on both the power and remote terminals, using the ground terminal as a reference.  If you have low voltage on either one, you might need to check the power line fuse, battery connection, or remote wire connection; low voltage on both usually indicates a bad ground connection.

If your amp is powered up, but showing a "protect" light, disconnect the speakers or subs from the amp and see if the light goes away.  If it stays on, and the power measurements are good at the power terminals, then it's likely that the amp is defective.  If the power light goes away when you disconnect the speakers, then you might have a bad speaker or the load impedance may be too low.  You can use a multimeter, set for resistance, to check the subwoofer voice coils.

A multimeter set for AC volts can also be used to check for an audio signal on the RCA cables that are plugged into the amp, as well as testing for power on the speaker output terminals.

If you'd like to send a follow-up with more information about just what your amplifier is doing, I can try to give you more useful troubleshooting ideas.

Hope this helps!

Brian