another not charging thread
Well, the ammeter on this car is long gone, it was in pieces by the time I got the car and the previous owner spliced the two wires together.
OK. Since you have a voltmeter you can still do a lot of diagnoses.
We'll have to assume the currents, and you can make some additional voltage drop comparisons.
Ignition: 2-4 amps
Rotor (alternator field): 2.5-5 amps
Brake lights: 2.5 amps
Parking lights: 4 amps
Headlights plus parking lights: 13 amps
Battery charging: 0 to 50 amps or more depending on how discharged it is.
Both locations show under 13v, though I think I saw over half a volt more when probing the alternator output.
Increasing current through a point of resistance will cause a larger voltage drop.
Conversely, when there is relatively low current flow, as is the case with just the engine running, there should be no measureable voltage drop.
My suggestions, if 67dart273 hasn't already made them, is to measure voltage differences in the circuit. This will remove the question of whether the ground circuit has resistance - in which case ground is not a good reference.
