Not getting 12 volts to coil

I'm surprised we have not talked about the two connections on the ammeter gauge, but I'm glad, even if you may be testing me to develop a test that would infer something about the ignition switch, my demon problem.

So. Yes the tests are to isolate and narrow down the problem.
What this one shows is there is resistance in the highlighted path.
upload_2021-5-7_9-52-32.png

I'm trying to understand where the probes were on this one, and was this also during the headlight on test.
I have .45 volt drop at my negative cable to the negative battery post and .4 drop at my positive cable to the positive battery post.

Is this where the probes were?
upload_2021-5-7_10-9-53.png

If so, then that is one step closer to identifying the location(s) of resistance.

Then check the first section (because its easy)
upload_2021-5-7_10-15-45.png

What you check next depends on a what you can access.
For example, you have long wire leads or maybe an aligator clip and some long wire, I've done this.
upload_2021-5-7_10-22-19.png

It can also be done by using the ground as reference. Use the same ground for both positions. Or at least what should be the same, like the body sheet metal.

upload_2021-5-7_10-29-8.png

Compared to inside.
upload_2021-5-7_10-32-5.png


IF you find the 2.4 voltage drop is all in the sections just tested, then there is no reason to access the more difficult to reach ammeter connections.


There may or may not be poor connections in the ignition switch, its connector, or the firewall connectors. What we are seeing is there is a significant issue before the electricity gets to the column connector or fuse box. We can't use the battery as a reference for testing when the votlage is dropping before it even gets to the main splice.