That's what I do to activate it.. I have the '17 model. Also, there is a place in the touchscreen under setting that activates Siri.
It sounds like you may need to update to the latest version of SYNC 3.2 before Siri will appear.i couldn't find anything in the settings, it's a 2015
I have a 2015 MKC also... You need to go to the Lincoln Owners Website. You need to Log-in or Register if you are not registered.i couldn't find anything in the settings, it's a 2015