Working on my buddies 2006 Sportster 1200 custom (carb). Last few rides it cut out on him a couple of times. We stopped and looked for loose electrical connections and couldn't find any. Ran fine for about 2 weeks without incident until he went to start it for the ride home from work. Would not crank at all. I got it home and started trouble shooting. 1) Battery fully charged and tight connections 2) All fuses ok without visible corrosion 3) All electrical connections clean 4) Ignition switch output checked on acc and run. Correct voltage output at each position 5) Can't run diagnostics as the display does not show up when put in that mode 6) Can see a very brief flash of diagnostic display when turning ignition switch from accessory to run. 7) Head light does not come on at all 8) Check engine light does not come on 9) Turn signals do light up along with oil and neutral light while ignition switch in accessory position. At 1st I was suspecting the ignition switch until I checked its output. Now I'm suspection the ECM itself. Any ideas?