Cessna Twin Piston Undifferentiated or Other Model
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Time Pressure; Other / Unknown; Human-Machine Interface; Distraction; Situational Awareness
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Diverted
Weather; Aircraft; Company Policy
We took off from ZZZ into what I knew would be consistent icing to our destination. From my pre-flight weather brief I knew the icing was at all altitudes. After departing ZZZ we actually got into the clear at about 5;000 feet with very little ice. About 15 minutes into the flight we again entered the clouds and started picking up light to moderate ice. My windshield began picking it up; so I went to turn on the electric windshield. When I did the switch broke off in my hand and the electric windshield was stuck in the off position. I decided to turn around immediately because I knew that it was clear behind me at 8;000 feet. I knew everywhere around me was overcast with an icing layer below me; so I decided to return to ZZZ. I notified ATC because I knew I was going to have to descend through ice and may get some on the windshield. I wanted to spend as little time in it as possible. We landed in ZZZ with no further incident. We only picked up a small amount of ice; but I was able to see just fine to land. The plastic switch broke; and I could not get the windshield heat on.
Cessna Twin Piston aircraft pilot reported the windshield anti-ice system was inoperative in icing conditions.