Hi Cavanman, thank God for your post! i am in the same problem, and lowered the transmission but wasn't able to find the grommet. Called Lexus melbourne and they said have to remove dashboard which is a absolute massive job.
Now i am just waiting for the borescope to arrive from ebay, then i can start rippppping the grommet!
Any tips on how to locate the grommet? i am guessing its middle of your copper wire and the endoscope?