The schematic is correct for wiring to the 12V out of a 300 Watt Power Supply Unit (PSU)
Now, I understand you that to replace the PSU for the battery pack, I need to run the battery's negative to ground. How? the arduino's? shoving it up my ass? the schematic is NOT for the battery pack, that's were I am trying to get to. The schematic IS for the PSU and it DOES work.
The circuit works fine from the PSU, the solenoid works fine straight from the battery pack, but when I switch the PSU for the battery pack I don't get the solenoid to pull. What gives?
If by this you are referring to a computer Power Supply box then where does the 12V AA battery pack come in ? Was that just a test power supply ?
So to make a long story short, you didn't realize that the power supply powering the solenoid needs to have a common ground with the uC driving the solenoid, right ?
I'm sorry you were upset but I did everything I could to tell you there was something wrong with the wiring.
@RunawayPancake,Thanks for correcting the OP's schematic , but if you look at his schematic and look at yours it is clear that the problem was more than a missing ground.
Can you please explain to the OP why his circuit would not work the way he had it shown in his schematic ?