How to change DRL settings etc?

[Janake]

Dear boys and girls what do you need to change settings for example the DRL ? My low beams is always on in auto, I want the DRL:s to come on. The DRL bulbs works OK when I after opened up the relay manually switched it so therefore I think it is the settings in the computer that has to be changed. I have a handheld scantool or do I need an OBD2 device connected to a laptop with a special program? My ´03 Tahoe is an export model. I also want to change my doome lights flashing into some lights outside the car to flash when I open or close with the remote key.
Excuse me if my English is bad I´m from Sweden.