2003 Nissan 350z..... i bought it used, and put a new sound system inside of it.... now all of a sudden, the sound system will not work, and my entire air system has stopped
Check engine light and the sound system may be unrelated. Also I'm not sure what you mean by air system (air suspension or AC?). For the check engine light you first have to get the engine diagnostic code scanned to know what it mean. You can get that done at many auto parts dealer (autozone). You can also get a scanner as cheap as $50 at sears (on sale). As for the sound system, take it back to the radio installer. If they did an amateurish job the wires could have shaken loose (or worse yet caused a short that cause the check engine light - unlikely). Good Luck...
