AJF,
Try this from the ST mobile app:
- Apps
- Explore By Device
- Brighten Dark Places
- Configure SmartApp
- When the door opens…Where? - Select your door’s MultiSensor
- And it’s dark…Where? - Select your luminance sensor
- Turn on a light…Which? - Select which light/switch
- Assign a name - Name it what you want
- Install
Jim