I had a flickering brake wear lamp too. Found when I changed the pads that one pad had worn enough to expose the sensor end slightly. The other three still had a hair or two of material left leaving the sensors fully covered.
I was surprised at the amount of pad left once the sensor made contact. Nice feature, no reason to ever get metal to metal.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.