Even with the relay control module, he still need to interface it to the OBD-II's K line. You need the relay control module to activate one of these
http://www.bypasskit.com/gmdl.asp?cid=11
With out the GMDL1, you need to do 5 wire door locks in driver, passanger and rear hatch then you need to do the neg trigger at the BCM under the rear seat to activate the rear passanger doors.