No Power To Amp!

[tech]

Hi there, I ran into an issue yesterday where the front audio and subwoofer cut out. I wired this system myself about 5 years ago, and it's been running great ever since.

I have a 4 channel amp with 2 channels running a front set of infinitys', and the other 2 channels are bridged for the sub. I also have a 2 channel LOC which I use so that I can keep my stock headunit. My car is a 2006 honda civic.

When I noticed the sound cut out, I checked the glovebox where my LOC is, and it was showing no power. I checked the amp, no power. I hooked up a short 10 gauge wire from my remote at the amp to 12v power, and the amp turned on. There appears to be power running through the remote wire OK. So I popped the hood and checked the main fuse coming off the battery to the power - it looked OK. I changed it anyway and it made no difference, so I changed it back. I then checked the power wire that's running to the LOC, it seemed fine. The fuse seemed fine as well. I changed it anyway, nothing.

I have my remote line coming from the interior fuse box (#35) of my 2006 civic. Pulled out the connection and checked both the 5A and 7.5A fuses, looked fine. Replaced them anyway, nothing.

I pulled off the front dash and checked for any fraying or burnt wires, didn't see anything. I'm pretty stumped as to what could be causing the issue. All the fuses seem OK, and the wires seem OK. I'm thinking the LOC might be dead as I still have sound from the rear speakers, as those are still run from the headunit, and not the amp.

Any ideas?

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[mxdano]

I am assuming that because you dont have power at both the LOC and the amp that they are powered from the same place. I would look there.

do you have a voltage meter that you could borrow?

 

[tech]

I am assuming that because you dont have power at both the LOC and the amp that they are powered from the same place. I would look there. do you have a voltage meter that you could borrow?

They're both powered off separate wires coming straight from the battery. Yes, I do have a volt meter.

 

[noble brown]

I am assuming that because you dont have power at both the LOC and the amp that they are powered from the same place. I would look there. do you have a voltage meter that you could borrow?

He's talking about the remote turn on wire from the radio. You said you jumpered the remote turn on at the amp to the 12v at the amp and it powered up but then you said that you seem to be getting power through the remote wire. Maybe I read it wrong but if you did jump it and it turned on then your remote wire is not getting power and I would be checking the place where you have the remote wire from the radio connecting to the remote wires to the amp and loc

 

[tech]

He's talking about the remote turn on wire from the radio. You said you jumpered the remote turn on at the amp to the 12v at the amp and it powered up but then you said that you seem to be getting power through the remote wire. Maybe I read it wrong but if you did jump it and it turned on then your remote wire is not getting power and I would be checking the place where you have the remote wire from the radio connecting to the remote wires to the amp and loc

OK, perhaps I accidentally misinformed you based off what I thought. When I jumped the remote wire at the amp to the power and the amp turned on, I assumed this meant my remote wire was good, and my power was bad. You're saying it's the other way around, and my power is good, but remote wire is bad?

 

[noble brown]

Yep that's it. The remote wire is just a switched 12v that only come on with the radio and turns on the amp so when you jumped it you supplied that 12 volts basically from the battery to the remote terminal. Check that remote wire. That's gonna be your problem

 

[tech]

Yep that's it. The remote wire is just a switched 12v that only come on with the radio and turns on the amp so when you jumped it you supplied that 12 volts basically from the battery to the remote terminal. Check that remote wire. That's gonna be your problem

That makes sense. I'll give it a try tomorrow and come back with the update. Thanks

 

[noble brown]

Actually now that I think about it you could be right. We could both be right, the only way to be sure is to do the test with the radio off and the car off (just to be sure). That way we can be certain that the there is no voltage at the remote wire. Then jump the 12v battery terminal to the remote terminal at the amp just like you did before. If it comes on with the car and radio off then it's definitely the remote wire. If it doesn't, turn the car and radio on , do the test again and if it comes on then than the problem is your 12v battery wire. Sorry about that I was tired and dealing with a sick toddler so I wasn't thinking completely coherently. My bad

 

[Boomin_tahoe 5,000+ posts]

I suspect the remote wire.

Everything else could be a solid connection but that remote wire is key for the amp to turn on.

 

[tech]

Actually now that I think about it you could be right. We could both be right, the only way to be sure is to do the test with the radio off and the car off (just to be sure). That way we can be certain that the there is no voltage at the remote wire. Then jump the 12v battery terminal to the remote terminal at the amp just like you did before. If it comes on with the car and radio off then it's definitely the remote wire. If it doesn't, turn the car and radio on , do the test again and if it comes on then than the problem is your 12v battery wire. Sorry about that I was tired and dealing with a sick toddler so I wasn't thinking completely coherently. My bad

I was able to successfully jump the amp with the car off and key not in the ignition. This confirms that the issue is with the remote wire. Furthermore, I did some voltage tests at various different points and found the power cable to the amp had the full 12+ volts, power to my LOC had about 5 volts, power on the remote in to my LOC showed 12+volts, power at the remote out of my LOC showed 5 volts, and power at the remote in of my amp showed the same 5 volts that the LOC remote out was reading.

Should my LOC be reading 5 volts at the power and remote out? It's reading 12 volts on the remote in.

 

[big scott]

ya should be 12v at the remote turn on wire only if your key is on.

so you need to start digging.

but i am confused you say your remote wire is coming form your loc ???

never used a loc so i dont know.

link to said loc would be nice...

 

[tech]

ya should be 12v at the remote turn on wire only if your key is on.
so you need to start digging.

but i am confused you say your remote wire is coming form your loc ???

never used a loc so i dont know.

link to said loc would be nice...

Sorry, I updated the post to be a little more specific. I have tapped into fuse #35 of my car and ran the remote turn on wire directly into my LOC, which shows the full 12volts. Then on the remote out, it's only showing 5volts, but that may be because the LOC is only showing 5volts on the power. Unless it's supposed to run at that voltage?

Here's a link to my LOC, AudioControl LC2i 2-channel line output converter for adding amps to your factory system at Crutchfield.com

 

[noble brown]

Just wanna confirm something. You said you have 5v at the remote for the amp and at the power for the loc? And 12v at the amp power and the loc remote?

 

[noble brown]

Then on the remote out, it's only showing 5volts, but that may be because the LOC is only showing 5volts on the power. Unless it's supposed to run at that voltage

Okay that is my guess. You should now be checking to see why you are only getting 5v to the loc power. Is it wired directly to the battery? Without it getting 12v there it may only be able to send out what it's getting through the power wire

 

[noble brown]

Just looked at the manual for the lc2i and I appear to be right. It's only gonna be able to send out what it gets in through the power. You should have 12v