I plugged my mini plug for my mp3 player in the aux port, but i dont know how to set the headunit to play through the aux plug

you said CAN , i bet you meant CAN'T or CAN NOT. right?
the AUX port is just a line input, analog audio input,
it dont know MP3 .
it only amplies the analog audio found there.
you connect any device, to AUX. push play on the device.
then put car radio in to AUX input mode and play. the audio.
that is all there is to it.
the external device does all the heavy lifting, reading a file, and decoding it (mp3 decode) and then sends raw analog audio out.

the cable is sold and radioshack, or walfart or many other stores,
Target, most MP3 players, come with this cable,
they use mini phone plugs, stereo, type,. (3 contacts)

By looking online I see there is a aux input for your system. Get a cable with a stereo mini plug on each end. This is the end you find on MP3 player headphones. Plug the cable in and choose Aux with your source button . You will have to turn up your volume on the mp3 player some, maybe half way....and could be higher depending on the unit. The RCA volume must be used also, set it to at least 25% and give it a try. Adjust MP3 player input down as needed.

Just plug the cord into the front of the cd player where it says "AUX" and then plug the other end of the cord into the headphone / line out jack on any ipod or mp3 player then select "AUX" instead of CD and the sound will come through the system

Buy a rca to aux 3mm plug then you can connect to aux port.
RCA out is for the signal to the amp from the Head Unit. Mic is probably for your cell phone.
Am pretty surprise that an HU like that doesn't have USB Ipod support?

You need to plug the iPod into the Aux socket, its on the front bottom right corner. Then you can switch by pressing "Mode" between playing either the CS - USB - SD - AUX.

To play iPod, select the "AUX" option.

press the src "source" button untill it comes up aux mode, you may have to go into another settings menu to activate the auxiliary inputs on the headunit

Try going through the menus and finding a place where you can adjust the aux level(volume) on my sony it has to be all the way up to match the output of the radio and cd functions-also my mp3 volume has to be up bout 1/4 to even hear it but when i turn it up it really goes then-i dont know if that helps but good luck

I have a 2002 Pontiac Montana and I use a 2 pronged RCA plug at one end with a yellow plug and a white plug, and the other end is one plug to use for the MP3 player. Plug your RCA plugs into the bottom 2 plugs. My RCA plugs on my cord are yellow and black the yellow one is in the middle
plug and the black in the bottom one and I use the AUX input for my MP3 player. I have a SANSA
and a Ipod and they both work fine. I hope this helps. Just a FYI so you don't think your radio is
going whacko after you do get the MP3 player to work the AUX will always come on first and you will have to push the AM/FM button on the dash or the steering wheel to get the radio or DVD back on.
And the DVD player will have to be switched on for the AUX to play the MP3 player.
Have fun...

Try from both ports on your Insignia and make sure you've turned the volume on it all the way up. On the car stereo, make sure the source is set it auxiliary (usually AUX-IN). Also double check your cord isn't damaged and plugged in all the way on both sides.

Hello,

I don't know if you have figured out how to turn the AUX port on yet, but I just figured it out. First, turn the CD Player off by quickly pushing the "Source" button. This is also the volume knob. Then, after the player is off, hold down the "Source" button. This will bring up the initial setup. Use the arrow keys to navigate through the options. One of the options is to turn the AUX port on. Once this is finished, turn the unit back on and you're ready to go.