There may be settings in the menu to select internal or external mic. Check your menus to see if you have the right option selected. Try a different wired mic to see if that works. Or check the mic's wiring to make sure it didn't get cut during installation - that's more common than you think. If you're trying to use the head unit's internal (built-in) mic, check the menu settings to see if there is an option to use the phone's mic instead of the head unit's mic. That might be selected by mistake.