This is what I did when I installed mine. I have the Axxess GMOS-04. You can get it here Axxess Class II OnStar Interface For Systems GMOS-04 | eBay. The only thing you will lose for the DIC is the date. Nothing else is affected. When you install the unit you will use the RCA connections from the back of your head unit to the RCA connectors on the harness. If you'd like me to pull mine and take some pictures let me know. You can PM me if need be.