Your voltage readings sound ?? partly because I don't know what right side and left side means. One side of the ballast is power from the ignition switch, the other side goes to the coil
WITH KEY IN RUN the switch side should be nearly same as battery. It rarely is, because the harness often has voltage drop.
The coil side of the ballast should show maybe 6-10V +/-. If it shows full battery, it means the coil is not drawing current, is open, or not getting ground through the box, or the box is not powered or defective
With the key in "start" and cranking, the coil + should be near full battery and in no case below 10V
HAVE YOU checked for spark and spark quality? "Rig" a solid core wire (can be low voltage wire if propped away from metal) from the coil tower to a spark gap tester, or a good plug gapped wide. Crank engine USING THE KEY. You should get snappy hot blue sparks at least 3/8 and typically 1/2" long
