You are guys are great. Thanks
I am finding the same thing with one off to the left for the dome switch.
I ended up with one extra-long optic cable and decided to run it from the left light pickup over to the right side for the "fourth" supply to the switches.
I assume this is what that one is for.
'03 E320 Wagon-Sold
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'65 911 Coupe (#302580)