mospeed

Tonight I got in my car and noticed my sub and rear deck speakers were on. so I checked my Kenwood KAC 8401 running the 3 speakers and it was not on. I checked:

amp fuse
amp 10gauge wire fuse at the battery
radio use 12V power attached too
ground wire

I also disconnected the Kenwood amp and placed the power, ground, and 12V wire to another MTX amp I have and no power either. I have been running this set up for 6 months now and all of a sudden it doesn't work?

Any suggestions???

Thanks,

lurch519

first thing i would do is replace the power wire that you are using, as it is wholly inadequate for the task. that amp is rated at 640 watts of power max. that means that amp, if it was 100% efficient, would draw as much as 55 amps of current. at 55 amps of current, you should be using 4 guage wire for any runs in excess of 10 feet, and i am sure we all know that it is more than 10 feet from the battery to the trunk (i am assuming you have your amp mounted in the truck).

if you hooked up another amp and it doesnt work either, they you may have a parital blow on the fuse. i am (again) assuming that you are using an agu style fuse (thick glass fuse) and what may have happened is that the solder point in the metal caps on the end may have failed, and even though the fuse doesnt look blown, it could still be open.

if you do your own work, i cant stress what djseto said enough. get a decent multimeter (i work in the car audio business and i picked up mine for about 30 bucks 4 years ago from radio shack) you dont need a top of the line snap on model or anything like that, just need to be able to read ac and dc voltage, as well as resistance. it is the most useful tool in my box when it comes to diagnosing electrical problems.

mospeed

Now I think about it, it is 8 gauge. I didn't think this amp would need 4 gauge... but I could be wrong. Yeah, the other amp I hooked up was a MTX 100W 2 channel amp, pretty small so even if the gauge was too small for the Kenwood, it should have powered the MTX small amp. And this set up was working fine.

But I will get me a voltage meter and check out the points. So I'm guessing I need to check:

1) Wire running from the battery terminal to fuse
2) Wire after the fuse to the amp
3) Wire RIGHT at the amp (same as #2, just further down)
4) 12V remote wire at the fuse and amp

Anywhere else?

lurch519

if the amp is wired correctly, then power wire should run directly to the battery, with a fuse within 12 inches of connection at battery

according to mecp study guide, for 50 to 65 amps of current draw, anything between 10 feet and 22 feet should be 4 guage. anything longer than that with that current draw should be 2 guage.

lurch519

^^my fault, misunderstood there.

mospeed

Thanks everyone, I'll buying a voltmeter tonight and checking where my break is. I'll keep everyone posted.

mospeed

Well I'm proud to say that I got the amp running again. I got a multimeter and checked where I was not getting power. I first check the amp + terminal. And I had 0V. I checked the battery and it read 12V... so a break somewhere. I went ahead and checked the remote wire terminal at the amp. It read 0V and 12V when I turned the car on. So for sure I knew I had a break in my hot wire. I checked the wire before the inline fuse and it read 12V. I checked after the inline fuse.... and there it was.... 0V. I moved around the fuse a bit and it read 12V after the fuse. :D

Looks like the fuse holder was a bit loose. Thanks everyone for the advice!