Electric outlet on dash above brake pedals on 3340. What is it??

[chief_jim]

Single blue or brown wire goes on flat blade of bakelite socket. Socket has a weird triangular copper contact inside. What does this thing do/
I looked at four 3340 tractors. They ALL had the same empty socket just above the brake pedals. Almost looks like it is for a light for the brakes??
Dealer has no clue.
Thanks,
Jim

 

[dave_peters]

Europlug electrical socket. It replaced the cigarette lighter type socket.