Frank,
Hope I don't confuse the issue further, but on my 2019 2552 (delivered in February), the switch that Jim and Junior refer to is not on the left side of the steering wheel, but is on the right side---to the right of the climate controls, centered between the two 12-volt receptacles in the dash.
Mine is a 3-position switch. Center is "Off". Pushed to the left connects the Pioneer to the Ford key switch--the unit turns on and off with the key. Pushed to the right connects to power independent of key--remains "On" whether the key switch is on or off.
All the best, Mike