factory amplified systems

I've been into car audio for almost 4 years and over the last year have been learning how to install. I try to work on as many cars as I can find. My friend that's a veteran installer has been teaching me but when i asked him about a car i wanted to work on he said don't touch it it's factory amplified and a pain to do. I understand why these cars are more difficult but how do you go about installing drop in speakers, or decks in these cars. My friend really didn't explain what you have to do to work on those cars very well, but i'd like to learn since i want to be able to work on whatever car i want. Also i've got a client lined up with a jeep grand cheroke w/ a infinity system that wants to add a deck and a single channel amp so i want to be able to put it in for him. any help is greatley apreciated.

also does anyone know of any availabe lists of cars that are factory amplified

For speakers, as long as the impedence is the same or higher, you'll be okay (it won't harm the factory amp).  Some systems use speakers rated as low as .5 ohms so the amp can produce more power.  If you were to use 4 ohm speakers with the factory amp, you'll lose volume since the amp is producing less power.  In extreme cases like this, it's best to just rewire the system (run new speaker wire from the new stereo directly to the speakers).

As far as installing a deck in these, it just depends on the car/system.  Infinity is usually not too difficult since you can just connect the lead labelled power antenna (used for factory amp turn on) to the remote turn on lead of the new deck.  The Grand Cherokee is no exception.  Bose is usually where you run into weird impedence values, and different harnesses, and unless you have an amp integration harness, a rewire is your best bet.  Many factory amplified systems have eq curves and crossovers built into the amps themselves, which will throw the sound off when you're trying to upgrade.

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My ex once told me I have a perfect face for radio.

well working on some factory amped cars is a pain but not all. in your case the factory amp is usually located behind the back inside pannel driver side. it will be a box with one or two wire harness's comming from it your.

most common speaker wire colors are
LF Speaker +/- GREEN/ orange - BROWN / red   +,- radio harness     
RF Speaker +/- purple - blue/pink   +,- radio harness     
LR Speaker +/- WHITE/ green - GREEN / WHITE   +,- radio harness     
RR Speaker +/- GREEN / WHITE - blue/orange   +,- radio harness     


2005 model
LF Speaker +/- dk. green - dk. GREEN/ brown   +,- radio harness    
RF Speaker +/- gray - gray/brown   +,- radio harness     
LR Speaker +/- dk GREEN/ dk blu - dk GREEN/ pur +,- radio harness     
RR Speaker +/- gray/dk. blue - gray/tan   +,- radio harness     


bose radios found in some maximas and such are a little different as they have bose speakers, individual amps attched to the speakers in there respective locations.
Not all bose systems are the same.

all radios with factory amps can be integrated into after market systems even elaborate cars such as mercades benz's have factory amps that are usually located in the back and can be messed with to.



Here is the key for you to do that grand cherokee if it is determined it has factory amp. take four lengths of speaker pos neg wire and run it to its location from the head unit mark the wires in many locations front right, front left and so on. than disconnect the amp do not leave it plugged in. find your wires and strip some casing and tap on to them or use T TAPS(not my choice) and leave the setup with the capability of being reversed.this process is if you want to get rid of amp and allow the new radio to control the eq settings and all. but thats up to you. you might experience popping if you use the new headunit with the factory amp.

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Jon
Installer/Help Technician
---coral springs florida---
mecp certification is not always needed. I have it and it has not helped me out at all. my experience out shines it.

With your infinity system, it should be cake. Most model years of the cherokee w/ infinity gold had the amp under the rear drivers side seat.
the amp has an input harness and an output harness..
the input will match the harness behind the radio. The output will more than likely be larger gauge wiring
seperate mids in the door, then midrange/tweeter in the dash, then rear full range, so a total of 6 outputs for the 4 inputs.
you can tie in the tweeter/midrange if they insist on being cheap and leaving the speakers in there.
if you're smart you'll get them into a component set up front, install your crossover in the back with your amplifier. then install tweeter in dash, midrange in door, easy, cheap and decent sounding (little brightness from the reflection of the glass, but most daily drivers won't notice it if the tweeter is in a -3db position

The only car i'll tell new people to stay away from is alpine digital systems in bmw (just time consuming due to vehicle construction)and a few older mercedes, lexus, and other misc. wood grain overlayed dash peice cars that are prone to problems when being pryed or pulled on by inexperienced hands.
Other than that most cars are a learning experience and well.. =) get in there and learn