Not getting 12 volts to coil
Making a schematic like these is helpful in visualizing how the circuit connects and works.
Here's a pdf you can download from 1968 where Chrysler suggests this https://www.mymopar.com/downloads/mtsc/247.pdf
The tests I was suggesting were designed to narrow down the list, and avoid digging into areas that are difficult to access if not neccessary.
Lets just go over the strategy.
1. Make sure the battery is fully charged. I assume you have some sort of charger whether automatic or manual.
2. Check for resistance in each power feed to the main junction.
2a Measure voltage drop between the battery terminal and the main junction with some moderately high current (engine off).
2b Measure voltage drop between the alternator terminal and the main junction with about the same current (engine running).
3. After establishing or correcting so there is minimal resistance in fees to the main splice, then check for voltage drops between the main splice and the ballast resistor.
3a. Resistance check of the key switch will identify a major issue there.
3b. Measure voltage drop between the battery positive and the ballast resistor, and the battery positive to the cavity in the firewall connector. Then you'll know if the problem is inside, or in the engine compartment.
Might as well look at and clean terminals for J2 and J3 wire while your in there.
It is the voltage that is reduced when current goes through resistance.
My diagrams are essentially tracings of the circuits of interest. They are from the same shop manual as you are looking at. Just reorganized a bit so its easier to see the flow.
Making a schematic like these is helpful in visualizing how the circuit connects and works.
Here's a pdf you can download from 1968 where Chrysler suggests this https://www.mymopar.com/downloads/mtsc/247.pdf
I Agree that those are the most likely places where there could be resistance. The battery terminal and the terminals at the relay and fusible link are also possibilities.
The tests I was suggesting were designed to narrow down the list, and avoid digging into areas that are difficult to access if not neccessary.
Lets just go over the strategy.
1. Make sure the battery is fully charged. I assume you have some sort of charger whether automatic or manual.
2. Check for resistance in each power feed to the main junction.
2a Measure voltage drop between the battery terminal and the main junction with some moderately high current (engine off).
2b Measure voltage drop between the alternator terminal and the main junction with about the same current (engine running).
3. After establishing or correcting so there is minimal resistance in fees to the main splice, then check for voltage drops between the main splice and the ballast resistor.
3a. Resistance check of the key switch will identify a major issue there.
3b. Measure voltage drop between the battery positive and the ballast resistor, and the battery positive to the cavity in the firewall connector. Then you'll know if the problem is inside, or in the engine compartment.
Yes. 16 connect the battery feed wire (A1-12red) and 18 connects the alternator output wire (R6-12 black)
Might as well look at and clean terminals for J2 and J3 wire while your in there.
Unless the evidence points to a bad welded splice, there's no reason to unwrap the tape to look at it.
Current in must equal current out. Picture it like a stream except instead of gallons per minute its electrons per second.
It is the voltage that is reduced when current goes through resistance.
