Sorry if I seem a bit one-track-minded, but try this.
Place the pre-tested 'other' model in as well, near the same light and compile to make sure it is being lit correctly.
Once it is, add this line somewhere
and see how it goes, ANY difference is worth noting.
If there is still no change, replace the above code with
and try again, see if the working model is still working.

Let us know both test results please...