I'm trying to install a small 300 watt amp in a '98 Civic LX. We have everything wired up just like we should, but the protection light keeps coming on. The only odd thing about this car is the factory AM/FM radio is behind the dash and powered to keep the keyless entry happy. I checked all the wiring, and the ground is good, the battery wire is getting 12.5 volts (car off) and the remote wire is getting 11.5 volts. With the input wire and sub wires disconnected or connected, the protection light is on. We put it in my car and it works fine, and we checked the readings in my car and they were the same. Anyone have any ideas?

 

Check to make sure all of the speaker wires are by themselves and what I mean by that is that no little wires (even one hair of them) are touching the others to short it out. Also double check your grounds and make sure you have a large enough gauge wire to ground it out. (Most sizes should work just make it a little larger than a speaker wire.) Also make sure it's grounded to non-painted metal and something that doesn't just go into plastic. Make sure it leads to the chassis.

 

As I said, even without the speaker or input plugged in, it won't work in the Civic. Grounds are fine as checked by my multimeter. Wire is 8 gauge for both power and ground and the amp is only 300 watts, so I'm good there. I've done this many times before, and this is the first time I've had trouble. All the readings I took were the same as what I got in my Prelude, where the amp works fine

 

change the fuse. it may look fine, but sometime they just dont work. are you running it off the same headunit? maybe its not putting out enough voltage through the the remote wire.

 

With all the inputs/outputs disconnected, if the protection light stays on, you have a fried amp.

 

said it works fine in the prelude.

Are you using the same wiring kit? If not just try to move the ground somewhere else. it may look good but who knows.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sony224422 &raquo;</TD></TR><TR><TD CLASS="quote">said it works fine in the prelude.</TD></TR></TABLE>

I missed that part. In that case, take your multimeter and check the voltage between the power and ground wires going to the amp. This seems like a bad ground.

 

Ground is good, all fuses have been changed and none are blown. I'm getting 12.5V from the battery and 11.5V from the remote wire in both the Civic and Prelude, yet it won't work in the Civic

 

what headunit are you using in the civic, and what about in the prelude? The only think i can think of is somethings funky with the remote wire then. Have you tried jumping power from the 12v constant to the remote input and seeing if it works?

 

Hadn't tried that because I wasn't sure if it was safe. I've got a Pioneer in the Prelude and an Insignia in the Civic. The Civic also has the OEM AM/FM powered, but doesn't have speakers or any other wires running through it. Just power

 

try jumping it to see if it comes on. If not, then try a new ground. If it does, then theres something wrong with the remote wire.

 

Have you checked voltage under load, I have metered 12.5V, [not under load] many times only to find it drop to below 10V under load, always to find a bad connection, [power or ground] at some point, most common is when AGU glass fuses are used, [amp power cable] they really are crap, and it can't hurt to check it again.
You are correct, it's strange that it works in your car but not in the other car, when everything seems the same, but obviously they are not the same, we know for sure the amp is good so it can't be the problem.

Let me ask you this, when wired up in your car, and working, does the protection light come on if you unplug the input and output of the amp, [like you tried in the other car]?
If not, that that eliminates a problem with the HU, the RCAs connecting it to the amp, or a short on the output.
That only leaves the power, ground and amp control lead, you can eliminate the control lead as the problem by doing test already mentioned by sony224422 use a jumper to jump from amps 12V+ to the rem. input, disconnect amp control lead from rem. input before using jumper, even a 1A-2A draw on the remote lead can be too much, and if the problem is in the power lead to the amp, the amp will try and draw enough current from the amp control lead to turn on, and if the amp needs more then the 1A-2A just to "idle" it can damage the remote output of the HU, you where right to be causes.

If the amp starts working when you do the jump the problem is the remote lead, if not, your down to the power or ground 94