Hi coolingtowerguy and welcome to the Ford Fusion Club. The "wrench light" can mean many things. And there is not practical way to blind Internet diagnose it. It could be anything from a false alarm, to something more serious where the vehicle should not be driven.Today the wrench light came on for the first time. Its got 120,000 miles with no problems and lifetime mpg average of just under 46 mpg. It's been a great car. Anyone had the wrench light come on and what was the problem?
I would also recommend you check your Owners Manual for the wrench light explanation. If you do not have your hard copy, you can download the PDF version here: https://www.fleet.ford.com/parts-service/resources/owner-manuals/
Ultimately, your best course of action would be to take it to a big box auto store like AutoZone, O'Reilly's etc, where they will scan your vehicle for any stored DTC's (Diagnostic Trouble Codes) for free. That may help give you some idea. Then it would still be best to have the vehicle checked by a Ford Dealer or independent shop you trust that has Hybrid vehicle experience.
Let us know how you make out and good luck.