Its an access hole to allow you to see what you are doing while trying to replace bulbs or remove or connect wires.

This is typically a dealer-installed option unless the modification was performed by someone else.


1955 1st GMC Suburban | 1954 GMC 250 trailer puller project | 1954 GMC 250 Hydra-Matic | 1954 Chevy 3100 . 1947 Chevy COE | and more...
It's true. I really don't do anything but browse the Internet looking for trouble...