My neon won't start. I have a BRAND NEW battery, starter, power cables, and battery terminals. My battery light stays on 25/8/366. I tested my alternator at several different locations and it passed everywhere.My car acts like it is getting no power at all. My gauges don't work and none of my lights will come in except on occasion. The car will jump start off of another car but as soon as i disconnect my car from the other, mine dies. I've been told that its either my ECU or wiring harness. I've checked all of my fuses and none are blown out. What's wrong!? Please help me before i just tow this thing to the scrap yard!

 

Grounds

 

sit does sound like a grounding problem.....
just out of curiosity....if the battery light is on all the time, is you battery temp sensor in the battery tray hooked up????

 

If you can jump it and it stays running with the cables attached but dies when they are removed, your alternator probably has no output and that will drain your new battery quite quickly. Have your local autozone or advanced test your alternator. I'd bet the battery in the car is pretty weak by now, if not totally dead.