Land Rover Repair: 2000 Range Rover HSE Tailgate lights, range rover hse, blbs

Question
All lights are out on my tailgate though the left and right quarter panel tail/turn/reverse lights work fine.  I find it very unlikely that all bulbs for multiple circuits would have burned out at the same time.  I have checked for wire breaks but appears to be OK.  I can't tell from the owners manuel if the tailgate light clusters are seperately fused.  Running out of things to check.
Thanks in advance.

Answer
If they are all out, and the blbs are good, I would suspect the ground wire or meltdowns in the sockets to one side or the other.  Power is supplied to the individual lights but ground connections are shared.

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Good luck
John Elder Robison