New to diesels and tuning. LML help.

Hey guys just purchased a 2013 GMC with the duramax. It has been deleted and I was told it has an EFI Live tune. It has a 5 position switch on the dash but no tuner unit attached. As I am new to these trucks, is there a way to determine what the tunes are? Purchased from a dealer that picked up truck at auction so no previous owner info. He told me that "normally" position 1 is stock, 2 is fuel economy, 3 towing, 4 & 5 are horsepower tunes. Is this "correct" or kinda correct? Should I feel differences when I switch the positions of the switch? Thanks for any info you can provide.

You won't be able to determine the tuner without the previous owner telling you who tuned it or without EFILive hardware.

The switch positions and each positions purpose is tuner dependent. What may be common for one or more tuners may not be common for others. Each tuner has the ability to modify many parameters so it is possible if 100 tunes were compared they could all be different.

Cheers
Cindy