Very simple blinker

F1 - Fuse 6A
D1 - Blinking LED 5V
D2 - Diode 1A/50V
R1 - 270 ohm/0.25W
R2 - 220 ohm/0.25W
T1 - Darlington's NPN 20V/10A
+In - 12V
+Out - "Blinking" voltage / max. 6A