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Could someone walk me through a head unit install?

2018 Views 5 Replies 2 Participants Last post by  hungwin jza80
I have installed a few stereos, but none on a car with a factory amp.

I have an Alpine CDA-7864 that I want to install in my 'dawg. Do I have to bypass the factory amp in order to use the power from my head unit? Will the factory sub still work, that is, does the stock wiring split the rear channels into the rear speakers and the sub?

I have read the other posts about using a '87 and up Toyota harness. I assume this goes in between the head unit and the factory wiring? I ask because I read a post where Ranger said that the harness should go between the amplifier wiring.

If someone could just give me the basic steps of installing a regular head unit, I would really appreciate it! :D

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Couple things to know when installing a stereo:

It needs a solid ground connection bare piece of metal is the best, try not to use the factory ground in the radio harness. Black on the alpine.
It needs a constant 12 volt supply, yellow wire on the alpine.
It needs a switched 12volt supply, red on the alpine.

Then there will be a blue/white or light blue, it should say remote out, this will connect to the remote turn on of any amp, or signal processor.

The rest of the wires will be other accessories and speaker wires. The speaker wires you will need a + and – to make music. Since the alpine is a 4 channel out, 8 sets of wires, ones with a black strip are the negatives.

Since your tt is factory amplified, is must utilize a remote lead (remote turn on), to be activated by the source unit (head unit). Here is what you should do:
Get a multimeter, preferably a digital one
Buy a mounting kit, and factory interface adapter plug
Remove the dash trim,
Make sure you purchase a factory interface plug connector. This is a plastic plug that connects using the factory harness, where by eliminating wire cutting.
Double check all the factory wires, for illumination, 12v, switched 12v, power antenna, ground, remote turn on.
The adapter plug is very simple to wire, match all the corresponding colours all but ground, you provide the ground as described earlier
Tape the wire connections very well, it is recommended that you solder them, but only real hardcore guys do this. On the factory out you will find the power antenna lead, remote turn on, speaker wires, power, switched, and ground, as well as illumination.
The only two wires you will not use are ground and illumination.
If you need more help, just post,
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Thanks for the reply Ear Candy.

I was unsure of how to treat the stock amplifier. After I had taken everything apart, however, it made sense. There are three plugs near the head unit and this is is where the '87 and up wiring harness plugs into. I was not sure where to hook it up before, because some people told me to plug the harness in by the stock amplifier.

I was under the impression that if you are putting in a single din head unit, you do not need a mounting kit. It will mount directly to the dash. Maybe you will need a Toyota plastic pocket to go under the head unit to fit the double din size?
Am I wrong, do you need a mounting kit? I am about to install a head unit myself.

This is correct, you will not need a mounting kit, there is a metal bracket that hold the head unit, that in turn is screwed into the dash itself. I filled the DIN-sized hole with a Blitz DIN panel that can accept two 1/4-DIN components (turbo timer, boost controller) and a 43 mm gauge. I can email you pics of my setup if you want.

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