2004 Impala Head Unit Question

[BryanHamade 10+ year member]

I have an 2004 Impala and am buying a Kenwood DDX712. I was told I need to buy a module so my onstar works and I get beeps when my doors are open. If I don't care about onstar or door chimes is there any disadvantage to not buying the module?

EDIT: Here is a link to one: http://www.crutchfield.com/S-YHtPdRDcBDU/App/Product/Item/Main.aspx?i=120GMOS04

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