I need to know the wiring schema for the 7 speaker infinity system in my 04 Dodge Quad Cab.
I am trying to find out what color wires are the postive and negative for the rear door speakers....AFTER The amp. Crutchfield sent me a schema but it is for the wires BEFORE the amp, I need to know after the amp. I am trying to install a sub crossover and I need to tap into those rear speaker wires to hook up an aftermarket amp. Where can I get this wiring schema?
Thanks,
Devan

 

I don't think that would be a good idea, You should go from before the other amp, the rear speaker output from the head unit.

 

But isn't the signal line running from the stock HU to the amp a very weak signal?

 

If that were true then you wouldn't even get a signal to the infinity amp. IF you go from the amp to the aftermarket amp, chances are you will blow the inputs of your aftermarket amp or cause alot of distortion since the inputs are rated for a lower signal.

And that is what an amp is for in the first place, to take a weaker signal and amplify it.

 

Okay...I'll connect in before the amp. It will make my life easier anyways, since I was cutting my hands all up trying to get two little wires twisted around in one of the tighest areas of the vehicle...right behind the glove box.
Thanks!!!

 

techmanbd...You were dead wrong. Splicing in BEFORE the amp did not all my aftermarket amp that is connected to my sub to respond to the volume being turned up and down. You could turn down the volume all the way to 1, and the low frequency was just as loud as I had it set on the frequency settings on the low pass crossover and my amp. I tried every combination possible between the frequency levels on my amp and on the crossover and still no success. SO, I finally ended up splicing in AFTER the amp and the sub responded to the volume control the factory radio. I had a feeling I had to be in after the amp for this to work.
Anyways this still isn't 100% perfect because I have all the levels cranked to the max on my amp that pushes the sub, and when I turn off the vehicle I get MAJOR reverb thru the sub. I cringe just thinking about it.

I am about to toss the whole idea of trying to get this sub and amp to work with this infinity system. Is there ANY after market head unit out there that will work with the factory amp and a wiring harness that will allow the factory amp to continue to function?

 

this is one of those challenging things. theoretically techmanbd is right. you should according to the theory of how things work, wire it up before that amp. i cant help you solve your problem, but i just wanted to say that techmanbd was not wrong, maybe not right, but not wrong.

Sorry to hear about your problems, i hope you work then out.

 

Here is the deal with that. The Head Unit communicates to the amp via a serial port that controls the volume, so getting another head unit wouldn't help control the amps volume. AND connecting an amp from an amp is not the way to go.

 

techmanbd...sorry for saying that you were 'wrong' ... I was extremely frustrated last night trying to get my amp and sub to work correctly....

Let me start over so I can try to find the best resolution for what I am wanting to gain.

I have a JBL BP600.1 which does not have a low pass crossover built on to it. It is a sub amp. I had it installed on my previous truck that I had an aftermarket HU installed with rca preouts...worked wonderful!
I am now trying to hook this amp up to my factory system in my 04 quad cab with the infinity system. I originally tried using a simple line out converter to RCA outputs...This did not work, it still allowed the high's to come thru to the sub. So then I purchased a low pass crossover, which I thought would solve all my problems. I then took techmanbd's suggestion of tapping in before the amp. I was pleased to hear that this would work, since getting to the speaker wires after the amp is NOT easy. You have about two inches worth of wire you can access to the R and L rear speakers behind the glove box. VERY awkward to try and splice into.

Anyhow...I tapped into the R rear and LEFT rear positive and negatives and hooked it into the low pass crossover and I had a lot of control with the crossovers frequency levels and the amps frequency levels, BUT when I would turn down the volume on the head unit, the sub would not quiet down.

So I ended up taking out the glove box again and hooking up the low pass crossover to the R rear and L rear speaker wires that were after the factory amp. This allowed the sub to respond to the volume control, BUT I had very little reponse to any of the frequency controls on the low pass crossover, AND I had to crank each frequency level control on the amp to the MAX. It also sounded like I wasn't getting the full potential out of the amp and sub. It doesn't sound bad, but I have that feeling in the back of mind that it could sound better...and I don't know where the problem maybe lying. ALSO, when I turn the truck off I get a HUGE reverb thru the sub, and I would at least like to solve that issue, but I have no idea where that issue may be coming from.

I would like to get an aftermarket head unit that has a sub RCA preout, so I can by pass all of this garb of tapping into speaker wires and the low pass crossover.

ANY IDEAS on what route I should take?
Thanks!

 

Accepted. I understand about being frustrated.

With the OEM infinity system, it is all digital now. The HU speaks to the amp through a serial port, and controls the volume through the amp. Also the HU through the serial com turns on the amp, so if you were to put in the Aftermarket head unit, you woukld never be able to use the OEM amp. Now on some OEM infinity amps, there is a channel made for subs. IF you can find the part number I may be able to tell you which one, and you can hook the sub straight to the OEM amp and see how that sounds. PM me the number. should be a number that is 4 numbers with two letters, 1111AA

The reason you don't want to ad the amp behind the other amp is the output is rated for a certain Ohms. If you install the amp in parallel you change the Ohms. And most likely what is happening with that noise is that the ohms is lower, therefore needing to drive the amp more, and causing the noise factor to increase.