Hey guys, I saw on here that a lot people seemed to have questions about the GS300 after market radio installation. So I just put a radio in my wife's car and thought I'd take some pictures during the install that might help you guys out. I was an Assistant Car Stereo sales and installation manager at Circuit City for 3 years so I have a lot of experience doing installs. So here we go:

I started by making a harness that was about 36 inches long to reach from behind the radio to the factory amplifier:

I left a quick disconnect harness on, like the ones at circuit city, incase I change out the radio later, this way I won't have to wire anything else up.

Next I dropped the glove box and located the factory amp and the output wires from the factory amp (an met 80 or 70 1761 from BB or CC will fit this harness).


Here's a close up of the harness and where it was unplugged from:


Factory Amp location on right:


Next I got 12 volt switched (accesory) from the harness behind the factory radio (not the factory amp) it is a gray wire:


Now I decided I wanted to try and keep the factory sub-woofer. To do this I wired in the sub-woofer wires (green w/red & green w/black on the small harness coming off the factory amp) to the driver's side rear speaker. The downside to this is that the factory sub and rear driver's side speaker are lowered to 2 ohms. It did not sound like any highs were getting through but it is difficult to tell since I can't fade the driver's rear off or it gets no signal. Here is a picture of the wires off the factory harness with the wires jumped from the driver's side rear speaker spliced and soldered on:


Next I grounded the radio to the gold colored bracket to the right of the glove box:


Here's a close up:


Last, I ran the wires along the same path as the factor wires and zip tied them in place:


And that was it. I soldered everything and I would recommend that you do the same. Time will tell if leaving the factory sub hooked up is a bad idea or not, but it definitely needed some bass when disconnected from the factory amp.
Justin

 

im slow with this so bare with me...

so you got the factory amp to work with an aftermarket radio?

 

he used the hu to power the sub I would have just kept everything stock untill having the complete system to go with a new hu

 

daaang, i 2nd that.

 

Well since it's the wife car she doesn't want or need a full system, but it did need a little more bass than 4"s and 5.25"s can provide. I still may take the sub off but it honestly sounds better with it on than it does off. I don't think having one channel at 2 ohms will hurt the head unit, if it does it is an old Pioneer 4400 anyway and won't be too costly to replace.
Justin

 

I see your point, but you are ether not using the sub as sub only, or you are not using the rear speaker as a mid range. I would have wired it different, but it's your unit your wiring. Also, I think you are running the rear channel lower than 2 ohms since the rear speakers are already 2 ohms plus what ever the sub is which I am not sure.

 

Hey,
The rear speakers are both definitely full range, I'm wondering since the subwoofer wires change color between the amp output and the sub if maybe there is a crossover built in somewhere keeping it lows only because it doesn't sound like there are any highs getting through.

I used a volt meter at the output from the aftermarket deck and checked the rear driver's speaker (the one I attached the factory sub leads to) and it read 2.2 Ohms. All the other channels read 4 ohms, Are you sure that on the Pioneer system the factory rear speakers are 2 ohms? The rear speaker with out the sub woofer attached was definitely reading 4 Ohms, not 2. I guess I need to stick my head in the trunk and look up and see what they say
Justin

 

Ok quick question why can't you use the factory amp with a aftermarket HU. I know cars with BOSE you can??

 

I am 99% sure it's 4ohms front and 2ohms rear, as for the sub, you may be right. It goes from green wires at the amp to yellow at the sub. I guess you just have to hope the deck is 2ohm stable and that your wife don't crank it at full for long periods

 

i did the same thing when i installed my avic d3, i wired my sub with the rear left spkr and wired my front and rear cabin mids to my front channels. i did that for months before i realized it didn't sound as good with an amped sub and eq settings for mid ranges tweeked correctly

 

That's because Bose amps each speaker individually rather than using a five channel amp like on our cars.

 

And in most cases the converters you have to use, WILL introduce noise...

 

Cool thanks for the info.

 

 

I think @lpher is talking about some of the old integration harnesses. Some of the one's that pac made had a noise problem. You still cannot integrate directly from the speaker outputs of an aftermarket HU to bose amps and keep the load at 4 Ohms. Most of the Bose speakers are 1 to 2 Ohms and the only way to keep them running off the factory Bose amp is to buy a harness that uses RCA plugs that plug into your after market HU's pre outs. This way the Ohm level is unaffected. So in that case you wouldn't be using your after market HU's speaker out puts. It would be like running the Bose amp as an aftermarket 4 channel amp. They have integration harnesses for Toyota which I bought for reading here fully thinking I would be able to integrate with the factory amp, guess I was wrong.
Justin