Sorry again. I forgot. Lua is one of those ridiculous languages that are case sensitive. So you have to use true and false in lower case for it to recognise it. Other wise it thinks they are just uninitialized variables. Also, as I showed in the example, GetCBusState returns a boolean so comparing it to 255 will always fail. try if GetCBusState(0, 56, 14) then SetLightingState(69, true) Also, I assume you are putting this in an event base script for group 14? Anyway, I tried it and it works fine now :)