Craigp, what series LS?/ model year?
1990 toyota celsior i believe its known as an ls400 also?
First thing, if not already done so, check for a break in the wiring in the left trunk hinge.
You will have to examine them closely as it may look good from the outside.
Popular fault, causes all kinds of wierd problems
cheers mate ill have a look today see if i can find anything