Yesterday I took my 1976 R90/6 out for a nice drive, weather was great and she ran fine. But I noticed at idle the brake failure light was flickering on and off. Front and rear brakes are working fine, they have good feel with nothing out of the ordinary that I can see/feel. What is the purpose of this warning light ? What is it telling me ? Now that I think about it maybe I should go check to see if the brake light ( bulb ) is working.