Please help aftermarket stereo issues!!
 

Hi I recently bought a new stereo for my 05 Pacifica, I took factory radio out put new one in nothing worked, plugged old one back in started car works fine, left car running unplugged factory radio and plugged new one in and worked perfectly... shut car off then turned it back on and new stereo didn't work again... so I repeated the same process and with car running unplugged factory radio and plugged new one in works great as soon as I turn car off and back on the new stereo won't work until I plug the factory in first and leave the car running,, does anyone have any clue on what is causing this I've never seen anything like it and am stumped! Thanks for any suggestions

1st, are you using a can-bus adapter? They are required for installing aftermarket stereos in newer cars.
2nd, are you disconnecting the battery while installing the aftermarket head unit?
(The battery must be disconnected during the install on newer cars.)

To be honest no I never thought about a can-bus adapter, I will give that a try and see how it goes, thanks for the help