Installing subwoofer+amp

[Richard Hopaneng Toennessen]

I bought a new car (a Peugeot 308) a while ago (September), and I’ve been wanting to install my sub and amp in it that I had while I had my old Peugeot 406.

I’m somewhat technical minded, but I do have one issue I’m wondering about, and that’s the remote cable for the amp.
Specifically, where do I put it?
The radio that’s in the car is one of the more basic models, meaning it has 1 cable for right speaker +, 1 cable for right speaker-, and so on and so forth – no one is labelled, and they’re mostly in the same colours. Because that would be too easy.
That is not the issue however, I got a LOC that connects the radio and the amp. The remote wire is the issue. 2 issues in fact.

The first one is, where do I connect it? Do stock radios normally have a “remote” wire?
If so, how do I identify it?
If not, where do I connect the remote wire? Many people (online) have said that I should just connect it to the 12v outtake-fuse, but my battery became drained in just 1 night, so that is not possible. Are there any other fuses I can connect it to, or wires that will yield the same result? As in, they will have power running through them when the ignition is on, but shut off power immediately after the ignition is off?

The other issue is (I fear) a more complex one.
The remote wire is killed on a regular basis.

I had the bass and amp in my previous car about 15 months, and in that time, I had to replace the remote wire 4 times!
The first one was a very thin wire that came with the amp (that was bundled with the signal cables), so I bought a standard copper wire 2x as thick, hoping it would last much longer. It lasted about 2 months, before I had to change it again. And again, and again. The last time I got a wire that was 4x as thick as the original, and it is the one I currently use.
Is there a particular reason why the remote cable should fry?
It’s right next to the signal cable, all the way from the amp to the radio.

Topic

[Paul]

In my limited experience, stock head units typically do not have a remote wire. Ideally, you want to connect the remote wire a 12V source when the radio is on, like the a power antenna (if your car has one), so that the amp is only powered with the radio. You could connect the remote wire to an accessory source that supplies 12V when the key is in the accessory and ignition position, but the amp will be powered whether the radio is on or not. Alternatively, you could add a switch between the 12V source and remote wire.

I kinda sounds like there is too much current flowing through the remote wire, causing it to overheat. I would measure the current between the 12V source and the remote wire – it should only be a few milliamps.

[zero]

The remote wire is simply to tell the amp to turn on, in the absence of a dedicated remote output “tapping” into the 12v switched to your deck would be the next best option. The head unit should have a constant 12V commonly referred to as the “memory” and a second 12V switched that actually turns the unit on. Some quick testing should easily determine that you have the right wire as the should be NO voltage with the key off, nor should the amp be on, most models have some sort of decorative or indicating LED on them.

From the problem you described as having it sounds like you tapped into the constant 12V supply which would have left the amp on at all times, causing the wire going to the amp to be energized with all the available current. You could simply install a fuse, 5 amps should be plenty. That should allow you to run the proper gauge wire.

Tapping into the power antenna would result in you amp only being energized when the radio is on.

[Andrew Phillips]

Look at the fuse on the amp. Once you know that, choose a wire gauge (AWG) suitable for that load. For example, if there is a 10A fuse on the amp, then you need a minimum wire gauge of 12AWG. A 15A fuse would require a minimum of 10AWG. As the wire gauge number gets smaller, the thicker the wire and the more current it can carry.

As for the remote, if you have a power antenna connection available on the radio, it can be used as previously stated, but I would use it to control a relay that would in turn control the amp’s remote, for safety. Here is a diagram:

If you don’t have a power antenna connection, you can use the same relay diagram, but connect the terminal marked pwr ant to any other circuit that is energized when the ignition is on.

Attachments:

• relay.png

[Richard Hopaneng Toennessen]

There are 2x 20amp fuses on the subwoofer.
Connected the remote wire to the fuse for the cigarette lighter to test, and it measured a measly 2 milliamp.
I also tried connecting the remote wire to the fuse controlling the radio, but even without the key in the ignition (everything turned off, even the lights inside) the amp stayed on. Is that normal? I sort of remember seeing somewhere in the car’s manual that it stays in some sort of “sleep” mode for 30 minutes or something, could that be why?

In either case, according to some site I found via googling (since the manual doesn’t have this information, there are apparently some wires for both the ignition and the antenna going into the radio, so I’ll connect the remote wire to either of those.

Think I’m going to try it tomorrow, need some wire clamps and -cutter that I got at work. Will post what I find!

[Andrew Phillips]

Cool. As for the power antenna connection, that should come from the radio itself. One of the wires on the radio should be marked for power antenna. It’s usually blue or blue with a white stripe. The radio provides 12v on that wire when it is switched on. The wire in your dash wiring would go to the fender, or wherever the antenna would be located, and does not supply power, it only delivers power to the antenna from the radio.

[Richard Hopaneng Toennessen]

Ah, aight, I don’t remember what the wires looks like atm, I’ll check it tomorrow 🙂

[Richard Hopaneng Toennessen]

So I’ve completed the install.

Connected the remote cable to the ignition wire on the radio, so it turns on with the key, and turns off a few minutes after the key is taken out (the sleep function I mentioned earlier – I suppose, it didn’t take more than 5 minutes for it to turn off).
There were 2 cables (aside from the big mess of speaker wires) going out of the radio. One grey, and one black. Neither were marked, so I didn’t bother with those. That’s why I put the remote on the ignition wire.

I must have connected 1 channel on the loc incorrectly though, as I kept getting rumbling from the subwoofer when the engine was on (nothing when the key was just in accessory). Solution? Unplug the left channel from the amplifier…

Can’t be arsed to rewire the stuff right now. Might do it later, might not. The bass did appear to be as it should, I will have to do some testing, and play my music normally, to spot any differences between my car stereo and home stereo.

Also, I did discover that I had originally reversed the polarity of the channels last I had attempted to install the loc 😀
Accidents happen…
This is why manufacturers should include wire schematics in the instruction manuals!

[Author]

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