ArdWrknTrk is correct. a lot of times when you have an aftermarket radio or an alarm system installed or anything that draws voltage while the truck is off you will be reading 12 volts. It is important to also raed the amprage of the circuit the same way by removing the positive cable and placing the amp meter in series with the positive cable and the positive battery post. Anything over 13 to 15 miliamps will start to drain your battery while the truck is sitting.

As for me my problem was my battery. First I did the voltage test and I was drawing 12 volts somewhere in the system. I checked how many amps the system was drawing and it was only 2.5 milliamps (which is not enough amps to drain a battery overnight). I took the battery in to Walmart to be tested and they said it would not hold a charge. Luckily the battery was within it's 3 year free replacement warrenty so I got a new battery for free. The guy I bought the truck from said the truck was sitting for a while and the lights were left on once which drained the battery. I assume thats when the battery went bad.

Thank you all for the wonderful advice and for the help of troubleshooting.