I would start by getting codes read. It needs a Powerstroke capable scan tool.
The front ABS sensors don't have anything to do with the speedometer, but the signal does go thru the ABS module.
Blinkers (turn signals?) would be a completely different issue. Have you checked fuses?
It's best to post tech questions in the appropriate forum. In your case 99 & up 7.3L Engine & Drivetrain.