The 1990-94 Lexus LS400's were bad for this as well. The wiring loom in the trunk is connected to the trunk hinge and over time the wiring will become twisted and frazzled and the wiring will fray and cause an array of electrical weirdness. No fires have ever been reported with it, but it does cause very strange things like warning lights on the dash illuminate for no reason, the transmissions electronics go haywire, etc, etc. The fix is easy.... simply cut away the tape from that area and splice/tape up the frazzled wiring and its fine. Seems as if the original wiring loom was too tight originally causing this problem, which is odd, because Toyotas of that era (80s-90s) are generally well-known for their excellent electrical systems.

Here is the loom in the trunk of my LS400 that has already been addressed... poorly, but it has been redone and all is fine now, but you get the general idea...