Does anybody have a picture of the accessory panel of the 3700 SCR in the cockpit between the steering wheel and throttles with the function labels visible? The panel with the engine blower. All my detailing has worn off. I’ve been through the owner's manual, but no luck.
The year of the 3700 SCR would be helpful. Have you been successful at testing the switches? I find it better to do at night. Dash and accessory lights are sometimes hard to notice in daylight.
You can also try tracing the switches behind the panel. There are typically spare Accessory switches which are not connected to devices.
Cockpit accessory panel
Linear Mode
