How to tell what programmer i need
 

So I just bought a 2006 dodge 2500 5.9l. It has a dial with 5 settings. But I cannot find anywhere where it says what brand of tuner it is. So I have no idea what tunes are in the truck right now. Anyone know how I can tell what brand it is so I can buy the right programmer?

The best kind! That's an DSP5 EFI switch 👍 1 is likely stock and 5 is likely the most aggressive tune

Awesome. Can I customize any of the settings?

the tunes will be preloaded (5 different) if you know the number of the prior owner I would try and contact then to see who provided the tuning.

If if they give you the tuners name You may be able to reach out to them and they can retune/provide specs for each tune. There is no way to go in and tweak it yourself without the EFI software.