It seems your mod disables the default "Enable conditon" and makes it so the lamps are always on when receiving the R,G,B, signals. I wanted to use them for a lot of fluid / storage level monitoring but I can't seem to get it to work.

On a different note: It also seems like they don't correctly illuminate their surroundings.

Yes, if either of these 3 signals are present, the lamp will turn on currently as it was easier for the use case that I created the mod for. I can change this, but I'd have to make it a configuration option, which would default to the current behavior (ignoring the condition).
You would then have to enable it in the mod settings, and maybe even increase the update frequency (depending on how fast you need the lamp to react to a signal level change), which can already be configured.

Actually, I have to reverse the earlier statement. This is currently not possible to do in a nice way (or I have yet to find it). As stated in the description the lamps must be always off via circuit condition (aka an empty one, or one that is never true) as otherwise the default lamp behavior activates, which will overlap with the modded behavior.

You can however still get what you're after, by adding an additional combinator to it. Instead of putting the enabled condition on the lamp itself, put it on the combinator and then have the R, G and B values be switched on / off via the combinator.

Basically you would have the constant combinator (or any other means) with the color values, and rather than hooking that up to the lamp, you hook that up to the input of the decider combinator, along with the wire that carries the signal you want to base the lamp on / off state on. The output side of the decider combinator would then be hooked up to the lamps. Said decider combinator would get the enabled condition you would set on the lamp, with an output of the everything signal set to input count. That way whenever your condition is true the lamps will receive the R,G,B values and turn on.