After rereading your post are you just trying to replace the heater switch in that part? I don't think it can be done if that is the case. You need the whole part. If MS doesn't have it I would either search the local junk yards in your area. You can also try www.thegalantcenter.net
to see if anyone is parting out another 8G. Post in the For Sale forum with a WTB (Want to Buy). Or just go to the dealership but your going to pay dealership price for a new one.