I just looked at the parts headlights I have. The ballast has 2 cables. One goes to the headlight bulb and the other has 2 wires ( power and ground ) There is an auto leveling motor but that is in its own cable.

When testing for incoming power and ground, be sure to use a incandescent test light that applies a load. A LED test light / digital meter do not apply much of a load and a marginal circuit will test good.