Ive installed a few of these on 03 and newer gm trucks and suv's. the H2 should be the same. If you have a by-pass module, the lock and unlock wires from the keyless entry box will be connected to the lock- unlock input on the by-pass. the by-pass wire will connect to the purple wire behind obdII plug. (solder this wire do not wrap it and tape it).Then you will need to follow the directions on learning the by-pass module by cycling the ignition. I know i wasnt very precise on all the steps but this will give you an idea. Also I only install directed electronis units. If you make all of your connections right, and make sure they are good, you will never have any problems with your keyless entry or remote start.