Jack Demmer Automotive Group » GRCC Members Go back to directory. Add to Address Book. Jack Demmer Automotive Group Jack Demmer Automotive Group Home 37300 Michigan Avenue Wayne MI 48184 home Home Phone: 734-721-2600home Home Fax: 734-721-2150homefax Personal Email: jdemmer@demmer.comINTERNET Website: Jack Demmer Automotive Group Categories: Automotive Updated 2 years ago.