Any updates Found the cause yet? .Its most likely as mentioned above in the main harness power distribution.Which requires some labor to remove it.Its less labor to go through the rear harness evaluation bulbs socket conditions grounds.And finish up with main or underhood wiring corrections.As Ive seen rear wiring harness get screws into wiring under rocker sill plate damages from carpet installed .Chaffed or tapped into. Stay with it keep us informed