1977VW T2 westfalia blinking light

[McP]

Hallo vom Biosphärenreservat Rhön
I have a green blinking light and have no idea why it's blinking or what it's indicating.
The manual says it should be the brake warning lamp, but this is not on the bottom of the dash, it's on the top.
The brakes also work perfectly. But should I look for and where?

Any help is welcome.