How to install an aftermarket stereo head unit?

If your vehicle has an Infinity amp and a CD / cassette combo radio, you removed one of the best radios I've ever worked on. All Chrysler radios can run with or without their amplifiers as, unlike with Fords and GMs, they only change the tone conditioning for the shape of the body. Chrysler amps don't increase volume or power. What you will find is the radios don't put out a lot of bass. That is made up in the amplifiers. If you try to run a non-Infinity Chrysler radio or any aftermarket replacement radio with an Infinity amp, you'll have too much bass unless you turn it down all the way.

If you're getting no sound at all from your new radio, the most common cause is the amp hasn't been told to turn on. That is done on the "Switched 12-volt" line that could also feed a power antenna. Your new radio will have a similar wire that must be connected. Typically it's a blue or yellow wire, but it will likely be labeled. Terminal # 1 in the black connector is the one that must have 12 volts on it to turn the amp on. That's the dark green / red wire.

The easiest way to bypass the amplifier is to buy an adapter plug that connects to the amp's connector. Do a Google search and they should show up. The alternative is to cut the wires at the amp, then splice each input wire to its mating output wire. For example, the "Left Front + In" gets spliced to the "Left Front + Out". There will be eight pairs of wires to splice, two for each corner of the vehicle. By doing it either of these ways, you'll keep the left front door and the left front dash speakers connected and in the system. Same with the right front. I added the drawings for the amp's plugs. Let me know if you need help figuring out which wires to connect.

For the benefit of others downgrading from the Infinity radios in other car models, many of them use speakers with their own individual amplifiers bolted onto them. They get their 12-volt power through a relay that is also turned on by the radio, so the same wire on an aftermarket radio will do the job, but it's not practical to bypass every amplifier if that is the way you want to go. It would be easier to just connect the new radio as before, then remove the really expensive Infinity speakers and install regular aftermarket speakers.