Receiver install in 2001 Dodge Caravan

I searched through old forum topics and didn't find anything applicable so hopefully someone out there can help. I'm trying to install a new receiver in my sister's Caravan. It has the Infinity stereo with what appears to be 8 speakers (2 dash, 2 front door, 4 in the back). She wants a cd changer but her current receiver doesn't have changer controls hence the reason for the swap. Keep in mind I've done about 20 receiver installs and never had a problem. My problem is I cannot get the new receiver to turn on the factory amps. After removing a door panel I was able to verify that each speaker has it own mini amp attached to it. I ordered the stereo through Curtchfield and they were of some help but they could not tell me how the factory receiver turns on these amps. The factory unit has two extra wires that do not connect to anything. One is WHITE/ violet stripe and the other is orange / YELLOW stripe. I stupidly tried connecting the amp power wire from the new reciever to the WHITE/ violet wire but this didn't do anything and luckily didn't hurt anything either. I didn't want to try the same thing with the ornage / YELLOW wire b/c Crutchfield was telling me it says in red letters not to connect anything to these two wires. Their suggestion was to find the GREEN/ grey wire that is the amp trigger wire and tap into this with the receivers amp power wire. This would be simple but finding the origin of that wire is not so simple. Also, if the factory receiver can trigger those amps, there has to be a way to get the new receiver to do so.

Has anyone had any experience with this car? Originally, Crutchfield insisted that there should be a blue wire on the factory harness which is the amp turn on lead but there is no such wire. I spent half of my day today (my day off) working on this and all I ended up with was getting incredibly frustrated and having to reinstall the original receiver.

Thanks in advance for any help.

That's weird because most of those infinity systems are a breeze to install aftermarket head units on, and there usually IS that blue wire present in the harness.  Did they tell you about the GREEN/ black wire?  Sometimes the infinity systems have that a GREEN/ black wire back there behind the dash and it has to be hooked up to ground.  It's the ground for the factory infinity amps, and has to be properly hooked up to a ground or else the amps won't turn on.

The wiring harness that you used for the head unit...is it the standard chrysler one that looks like this?:

http://www.crutchfield.com/cgi-bin/S-JyP4TJOfBTb/ProdView.asp?s=0&cc=01&g=103000&id=morephotos&pi=2&i=120701817&display=XL

The wire all the way on the left is the blue wire they were talking about, and if its not even present in the harness that crutchfield gave you then it's a defective harness.

Probably what's happening is the harness is fine, it's just that there's not actually a factory wire in place on the factory harness, where the blue wire's pin would hook up to in the factory plug.

This is exactly what I did, sort of. After talking with Crutchfield, I finally got it through to them that there was no blue wire in the factory wiring to turn on the amps and they must turn on them through the car's computers. So what I did was I ran a jumper wire in the fusebox and now use the fuel pump relay to turn on the amp relay. Works perfectly and was quite easy (no wires to run through the firewall). The pump relay is switched on when the ignition is on.

I did not want to go the FM modulated route mainly for ease of use. My sister has two rowdy kids and having everything hidden away is my best chance of keeping everything in working order. I hid the changer under the front passenger seat in the factory storage bin (cut the snaps off so the door fold down to give access to the disc magazine) and hid all the wiring aside from about 3 inches next to the seat.