For the first time since i have owned my truck it had a hard time starting. I have started it when it was -25 and it started like it was nothing. Now it is only-2 and it took a while to get it started. Then when i was driving it the batter guage went to zero. Then i restarted it a few times it started fine. But there are 3 codes now P0633,P2509,P2503. If some one could tell me what thoses codes are that would be a big help.

 

Is it cranking through normal and just won't hit or slow cranking?
If won't hit, check for codes would be good start. There is web site for codes mentioned in other threads. Do search for those.
If slow cranking, pull the alternator and get it bench tested.