2008 suzuki xl7 when you turn key to start the dash board lights go out and nothing happens what could it be?

It sounds like there is a connection problem. Check to make sure the ground to the engine block is clean and tight. Make sure the battery terminals are the same. Also, check all fuses and relays under the hood in the relay box.

already checked that anything else it could be

There has to be something electrical that can't maintain the electrical supply. That is why I'm thinking relay.

i switch the relays out and still nothing would it be something with antitheft or nuetral safety switch

Have you checked for codes?