Ok, let me try to make sense of all this

[Drew]

Ok, yet another wire harness/ install thread.

If I buy an aftermarket head unit, I need a wiring harness (obviously). My understanding of a wiring harness (from previous cars' experience) is a plastic plug that "plugs" into the factory wire harness. The other end of this wiring harness then just simply plugs into the back of the new head unit. Is this true for the Celica GT-S with the premium sound?

If it is true, my guess is that the factory wiring harness probably runs through the factory amp. Correct?

But I heard running through the factory amp causes road noise through the speakers. Is there a harness that bypasses the factory amp?

All help is appreciated.

[carbonyota]

I def wouldnt run the factory amp (if thats even possible) with an aftermarket headunit considering most are preamped already. I just hard wired from the factory amp harness with extensions to my alpine harness. Its not hard and I'm pretty sure its in installs for the wiring colors.

[skamikaze]

drew youre right on the money. basically id consider upgrading everything if you have the premium stock system. if you dont get a new amp, you can wire it up bypassing the stock amp and have it sound alright (but it wouldve sounded better stock). or you can wire it up and have the distortion. if you dont think you want to upgrade your sounds at all besides the headunit. you may want to consider one of these converters like this: <img src="http://www.soundgate.com/products/cd/photo/OEM4A.gif">
it'll integrate the use of the stock amp, but turn the levels down so it will be clean and free of the distortion. the only thing is i think it runs for about $50-$100. so thats why you may want to but that money towards a new amp or something :)

[skamikaze]

oh by the way, i forgot to mention, that device is the OEM4A from soundgate.

[Drew]

Ah I see, I would prefer not to get an amp. Back in the day, I used to have my whole trunk filled with subs, amps, crossover, etc...I really have absolutely no desire to do anything like that again. I would prefer just a clean install. I know the head unit I want is the standard 50W x 4 max power. I don't know if that's better or worse than the factory amp power. Something tells me the factory amp is 180 total watts. I could be wrong though. I guess I am having problems understanding why the sound would be worse with just a head unit vs. the factory amp???

I really want the head unit because I want to be able to play MP3 CD's.

skamikaze: Will that little converter work for our cars specifically? Anyone have any experience using such a thing?

[skamikaze]

i think it's universal for cars with a factory amp (including other toyotas). you may want to go to a shop and refer that company/device to them and they should be able to explain it more if they know what theyre doing :) i personally dont know much about it other than it works. i know of two people who have it in their gt-s.

[Dep613]

Will this OEM4A work with the Schoche TA03 wiring harness? Could it cut the whine out of my system?