The re are 3 wires or electrodes on all starters. One is the large bolt that is attached to the main positive battery cable. One is the small wire that is sometimes purple that is attached to the ignition switch “key”. And one is just a copper wire or electrode that supplies a ground/power to the starter from the solenoid.
Tested the headlamp using the ballast on the other side (co-driver) to confirm that the ballast isn’t the culprit. It ended up being the same.