I cannot see an obvious break so I am thinking about splicing a wire into the backplane at some other point so the ground comes in from two directions. Anyone ever tried this?
I also found a complaint filed with the NHTSA. For those that are interested here is the pointer: http://www.nhtsa.dot.gov/cars/problems/
Drill down by looking at "consumer complaints" then "vehicles" then choose, in three steps, 1994 Lexus LS 400 and you will see case ODI ID 857012 filed about the instrument lights. Strange but there are no 90-93 LS 400 complaints. I have ordered the file, will investigate and update this forum.
Based on what I have read on the Lexus forums we may be onto a large-scale 1994 LS 400 problem where many people have, and are paying $1100-$1500 to correct a factory defect!