brake light flashes

Sounds like your ABS system has a fault code stored in memory. A code 1 is a problem with the ABS ECU thus the 1flash. A code 3 is an open dump valve code, thus the 3 flashes. Best to see a shop that knows how to deal with an ABS problem: http://repairpal.com/chevrolet-repair-in-west-suffield-connecticut