how does it ground ??
Part of it is the power supply.
Answer this. What is the max voltage the battery can supply power at? What is the normal votlage range for the alternator to supply voltage at?
Up to the welded splice current from each follows a different path.
Test for resistance in each using voltage drop.
Begin with a charged battery (use a charger) In fact for the is test you in some cases you could leave the charger on it.
Turn on something that draws power. The more power going through resistance the larger the voltge drop. V=I x R
The ammeter will show how much current is getting drawn from battery.
Measure the power supply voltage. Then go measure voltage differences from the power source (Bat positive) to other accesible locations along the feed circuit.
Then remove the charger, start the car and let the battery charge back up. When the ammeter shows zero charging, do the same checks as above but from the alternator's output stud.
Unless you have or make very long meter leads you may not be able to measure voltage drop all the way into the passenger compartment.
Options are:
A. Cheat. When the battery is supplying power, use the alternator's output wire as a lead extension going to the main splice.
^^This is actually a great place to begin.^^ It quickly reveals if there is a voltage drop between the battery positive and the main splice.
If there is none, or very small, then that whole feed line is OK.
Then start the engine. Once the battery is charged, turn the lights on, and do the same but with the high voltage lead (red) on the alternator poutput stud.
B. Measure voltage to ground, and subtract from voltage at power supply. This assumes no resistance in ground circuit. You can also check that, at least for the battery. Measure the votlage differnece from some place on the chassis to the battery negative terminal (not the clamp, the terminal) with the lights on or whatever your test item is.
Diagrams illustrating the method here:
https://www.forabodiesonly.com/mopar/threads/voltage-problem.541822/post-1974321021
Part of it is the power supply.
Answer this. What is the max voltage the battery can supply power at? What is the normal votlage range for the alternator to supply voltage at?
Up to the welded splice current from each follows a different path.
Test for resistance in each using voltage drop.
Begin with a charged battery (use a charger) In fact for the is test you in some cases you could leave the charger on it.
Turn on something that draws power. The more power going through resistance the larger the voltge drop. V=I x R
The ammeter will show how much current is getting drawn from battery.
Measure the power supply voltage. Then go measure voltage differences from the power source (Bat positive) to other accesible locations along the feed circuit.
Then remove the charger, start the car and let the battery charge back up. When the ammeter shows zero charging, do the same checks as above but from the alternator's output stud.
Unless you have or make very long meter leads you may not be able to measure voltage drop all the way into the passenger compartment.
Options are:
A. Cheat. When the battery is supplying power, use the alternator's output wire as a lead extension going to the main splice.
^^This is actually a great place to begin.^^ It quickly reveals if there is a voltage drop between the battery positive and the main splice.
If there is none, or very small, then that whole feed line is OK.
Then start the engine. Once the battery is charged, turn the lights on, and do the same but with the high voltage lead (red) on the alternator poutput stud.
B. Measure voltage to ground, and subtract from voltage at power supply. This assumes no resistance in ground circuit. You can also check that, at least for the battery. Measure the votlage differnece from some place on the chassis to the battery negative terminal (not the clamp, the terminal) with the lights on or whatever your test item is.
Diagrams illustrating the method here:
https://www.forabodiesonly.com/mopar/threads/voltage-problem.541822/post-1974321021