it is not likely to be a component.
it will be a connection.
that wire goes to the giant splice on the wiring diagram, then into the bulkhead connector, which is the most likely problem.
then it goes inside to the ignition switch, not sure if it is column or dash mounted. column mounted means another connector at the base of the steering column.
the ignition switch.
then back to the amp meter
then back through the bulkhead connector which could be the problem too, or combination of in and out.
then to either another common hot or to the battery.
you will also need to validate the grounds give you the same voltage. using the battery neg post and vr body. which you did earlier so you should be good. but just be careful using whatever is closest as a ground when you are inside vs in the engine compartment.
and you will have to do this with the key in the run position for power.
careful not to zap anything.
when you split the bulkhead connector you will probably see the corrosion.