Trying to help my mom here...
2009 Chevy HHR with onstar, has Onstar butons on the mirror. Would like to upgrade the mirror to one with a compass and map lights while retaining the Onstar. Just get one from a wreck and plug in? Or will I have to do computer wizardy to keep onstar working with new unit? Just an extra wire or two for power on new accosserys?
