Usually the gauge cluster will have wires running for each individual gear position to the shifter unit. Also, if they are in the wrong spot on the pin in the cluster, not only will they not light up, but if the reverse lock out is in the wrong spot, it will cause the tranny to shift roughly when you move it from park, rev. I don't know about the illumination on the element, but if the numbers light up it is probably a dash light issue, or a burned bulb in that particular spot, although I don't see how that works.hmmmm thats good to know since mine dont either. maybe i unplugged something when i was in there last.
i just look at the one on the dash anyway