On the dash its reading 9 volts and every now and then the car will stall out if I have the radio and the headlights on. Also it dies very fast if I leave the door open for more then a minute the car won't start. Went to autozone and the Alt is reading fine and the starter is fine as well. If it helps I do have a after market head unit and a new battery.

what kind of car are you talking about?? could be just a bad battery??

could very well be a bad battery or a least a low one. Take a reading at the bat when it is running and see if it is 9 volts. If you only have 9 volts I doubt if the car starts without a jump. Give us some more info. Mark

Nope its a brand new batter fresh off the shelf. And its reading 12 volts 14 running off the alt. So I'm Kinda lost maybe my guages are broken?

I know its new ,but the symptoms still sound like a bad battery.

Where is the battery mounted?Is the ground to the engine block and to the body of the car good? As in solid ground straps and clean- to- the- metal spots?

I had a low voltage problem as well, I changed the alternator wire from a #10 to a #6 and cleaned up the power connections on the horn relay. I have a one wire 105 amp alternator and a stock harness, the #10 was big enough with the old 45 amp alternator but not the high output ones. I gained almost 2 volts on the guage after the change.

With the electrical system powered up and showing 9V, measure battery (+) to a known bad power point (where you're seeing 9V). Note the measurement and repeat on the ground circuit. Measure from the battery (-) to various grounds like the dash, voltage regulator, light harness grounds etc. Note the readings there as well. If your readings show more than 0.05V or so, you've found a bad connection in the hot or ground circuits. I suspect one of those test will show 3 volts and we can narrow it down from there with more tests.