On the A330 the panel lights come from a independent part of LGCIU 1. Even if LGCIU 1 has failed as long as it is electrically powered the sensors for the gear lights in the panel will still work.
So to summarize:--- there are 3 proximity downlock sensors on each gear, system 1, 2 and the independent.
Edited for the third time!!
Last edited by nitpicker330; 10th June 2013 at 08:49.