Can the wheel email winners before their code runs out?

Yes. Switch on Remind winners before their code expires under Settings → Expiry Reminder. Each winner then gets one email from 10:00 on your store's clock, Days before the last day before the code stops working (2 by default), with the code, the prize, its last day, its conditions and a link that puts the code in their cart. It is sent only while the code is unused, published and not yet expired, only once, and, where your form shows a consent tick box, only to winners who ticked it. Send me a test sends you a copy with a sample code. It follows its own switch, not the wheel's, because a won code keeps working with the wheel off.

It is on for new installs. If you had the wheel before, the Dashboard offers it once while the wheel is turned on; it then covers codes won from that moment on.