HU Install problems with stock amp

Are you sure you did all the connections correctly?    Where/what did you plug the TA03 in to?  Your symptoms sound similar to what happens when you try to connect an aftermarket radio to avalons and camrys with the factory amps.  The plugs coming out of the factory radio will lead to other plugs about a foot away, and you unplug those and plug in your TA03.  I don't know if this is what your situation is but give it a look.

Sorry if this is confusing, I'm still trying to visualize all that you've described.

It's probably used to match the eclipse's line out voltage with that of the factory amp. And considering the eclipse has a really strong output signal (8 volts) you might need to use this to bring down the level a bit before you send it to the factory amp.

One more thing I just found....on installer.com, for the 00-01 celica they have an amp bypass harness listed. The picture says it's 17 feet long, which makes it sound as if the factory amp is in the trunk, but I know the amp is behind the glove box. Weird. I know you're not looking to bypass the amps but I wasn't sure if the picture might give you a clue as to how to do some of the connections. I'm still trying to figure out the other stuff though.

Oh yea and I also wanted to ask you if this was what the harness you're using looks like? If so, what did you hook those two loose black wires on the left side of the picture up to?

thanks so much for taking the time to help me out. that is the harness i am using, plus it comes with this https://www.sfxaudio.com/products/dispItem.asp?ProdId=80205 the official name for it is the high level amplifier interface...4 channel level converter, whatever that means! those two black wires you are referring to are ground wires. i grounded them together. and i grounded the headunit ground wire separately.

im sorry but i really dont understand how that picture helps me, im a noob :) and yes my goal is to retain the stock amp. if you bypass the amp, ive read you have to wire the speakers in series, plus you lose mid and bass. it's still there, jus much weaker.

i see what youre saying about the eclipse 8V signal needing to be turned down, and thats what im assuming the "high level amp interface" is used for, but again i dont understand how i connect that to both the harness and the eclipse head unit since i only have enough rca jacks to accomodate one of the two.

on that website (installer.com) with the factory amp bypass harness i noticed there was an eclipse 16 pin connecter with speaker wires that could wire into the "high level amp interface." would that connecter fit in the headunit and solve the problem?

before i try that im prolly gonna try splicing the speaker wires running into the amp to that high level amp interface again. i was thinking maybe last time i forgot to plug the speaker harness back into the amp when i tested out everything. but again, i doubt that's the problem because the real reason i didnt get sound is because the headunit didnt have any audio signals going out right? i mean since the headunit's connector doesnt run speaker wires, if i dont connect those RCAs to something, i wont get any sound correct? this is damn frustrating because i dont even have my car to work on. i have to wait till monday because i have it stored in a garage at my parent's house...sorry these posts are so long to read!

I wasn't sure if that picture would be of any help or not, just thought I'd include it for the heck of it just in case.  I figured those were ground wires but I wasn't totally sure.

High-level interface means that it converts an amplified signal ("high-level"), such as that from a standard head unit's speaker outputs, to a low-level signal that you can then use to hook up to an amplifier.  Usually you would then hook up the converter's RCA outputs to an aftermarket amplifier.

The main problem you're running in to is that they don't really make RCA-to-speaker level converters--cuz well that's what an amplifier does.  You can get a low-to-high level line driver but the only ones I've found only have RCA outputs.

I think what you might want to try is this:  use something like the FD03 and just cut the ford connector off, then use the bare wire ends to tap in to the inputs for your factory amp (Each RCA plug would have a positive and negative, and would be for each speaker).  I know you have 8 speakers but I'm almost positive the factory amp only uses 4-channels of inputs.  If you decide to try this approach, you'll also need 2 level controls so that you can step down that 8volts from the eclipse, to match the factory amps.  What I had in mind was something like the N-22V, but you need two of them to be able to adjust the level for the front and the back.

You could always try the ford RCA plug thing without those level controls, as the factory amp's input might be of a high voltage.  You won't hurt the amp, it just might be really really loud even with the eclipse's volume turned down.  If that does happen then you know you'll need to use those level controls.

Unfortunately I do not know the color coding for the factory amp so I'm not sure which wires to have you hook up to, but most likely they'll just be the same color as the ones coming out of the factory radio plug.  And since you bought an aftermarket harness adapter thingy, you can hold up the two plugs next to each other and figure out the corresponding speaker pair.  make sense?

oh yea and the level control thingys would plug in to the head unit's RCAs, then you'd take the controls' RCA outputs and connect those to the FD03.  Good luck, hopefully it all works out!

no that's a piece you suggested i buy (two of them)
"The N-22V is a passive stereo potentiometer designed to control the signal level feeding an amplifier, equalizer, electronic crossover, etc. The N-22V has a stereo pair of RCA inputs and a stereo pair of RCA outputs. It's important that the inputs and outputs be connected correctly. The outputs must feed and amp and the inputs must go to the source (i.e. deck.) That's it. When the black knob is rotated clockwise, the signal increases up to the maximum output of the source. When the knob is rotated counter-clockwise, the signal decreases all the way to zero volts (system mute)."

but now im thinking at $20+ each plus shipping. it's kind of not worth it. might as well use that money toward a decent amp

oh yea...sorry bout the brain fart.   ANYWAYS, I definitely agree with you about the cost of the control thingys.  And I guess trying it out first without those would still involve buying that other harness (which, if you ended up using an aftermarket amp, you would not need).  Quite a dilemma, huh?  In the end I really think you'd be happier with the sound of aftermarket speakers and an aftermarket amp, though that's gonna be a lot more money than these converters and stuff.  But without a doubt it'll sound ten times better.  So the question becomes, is that difference in sound worth all the extra money?  are you content with the way the stock speakers sound?

im content with how they sound, but i guess since i know im gonna upgrade in the future, i might as well take the next step. now it's jus more headaches of picking what i want to replace the fronts with...lookin at a/d/s 346is...