That's a VERY low voltage reference signal from the pick up coil to the module, so it doesn't take much corrosion to make it a dead player...
I'm headed out your way again in just a little bit, Quantico this time...
Like the people out that way once you get out of DC...
DC people are like all 'City' people, the folks that are just plain folks are pretty easy to get along with!
One thing I would check, with a test light,
Hook to battery POSITIVE,
Probe negative to make sure you have a good connection, and test the 'Test Light',
Then I'd pull the coil connector off and probe the 'Green' wire terminal in the coil connector.
If it 'Flashes' when cranking, then you DO NOT have an issue with module or trigger.
If it Does NOT flash while cranking, then it's time to start looking into module or trigger.
I'd probe the 'RED' wire in the coil connector to see if you get 'Bright' light while cranking,
This will tell you if the 'Red' 'I' terminal to the ignition coil is getting full power when cranking,
And a dimmer light when the key switch is in the 'Run' position...
When key switch is in 'Run' position, the power is going through the ignition resistor (Which may have given up) you should have reduced power to the ignition coil.
Module HARNESS side
should have 'Blue' wire (Connects to module 'White' wire) showing full voltage while cranking,
And the HARNESS side of module connector
should show full power with the key switch in the 'Run' position.
If the module is getting power, and the coil is getting power, and the 'Green' coil connector wire test is showing 'Ground' through the module, then it's the module or the distributor trigger...
You are fixing to replace the distributor trigger, which should rule out one of the potential issues, but never discount getting a bad module from the parts store, it's happened to plenty of us!
This is the wiring diagram for your ignition,