Flickering or pulstating Headlights
Lets just walk through a couple of voltage drop scenarios.
First one is fairly obvious. If current is flowing from the battery, a poor connection at the battery positive terminal will result in less voltage at every point downstream.
Next is the same system, but with two bad connections.
One bad connection on the alternator output wire at the bulkhead.
The other bad connection on the ignition switch feed at the connector.
Notice the alternator stud and the battery are at the same voltage.
The voltage drop is after the resistance to the current.
So everything after the ignition switch connector might read 11 Volts with the 2 amps going through.
Turning on the heater fan would increase the flow though the switch and voltage will drop more.
But turning on the headlights would not change the situation.
J would stay at 11 Volts (assuming the battery voltage stayed at 12.5 Volts).
Notice in all of these tests the alternator output wire is just an extension of the test probe.
To check the condition of that circuit, we will need to repeat the tests with the alternator running.
These are just examples. Also your circuits are different. Sketch out what you've done and then you can come up with tests to narrow the areas to look in. Sometimes its just as easy to take connectors off and do visual checks first.
Lets just walk through a couple of voltage drop scenarios.
First one is fairly obvious. If current is flowing from the battery, a poor connection at the battery positive terminal will result in less voltage at every point downstream.
Next is the same system, but with two bad connections.
One bad connection on the alternator output wire at the bulkhead.
The other bad connection on the ignition switch feed at the connector.
Notice the alternator stud and the battery are at the same voltage.
The voltage drop is after the resistance to the current.
So everything after the ignition switch connector might read 11 Volts with the 2 amps going through.
Turning on the heater fan would increase the flow though the switch and voltage will drop more.
But turning on the headlights would not change the situation.
J would stay at 11 Volts (assuming the battery voltage stayed at 12.5 Volts).
Notice in all of these tests the alternator output wire is just an extension of the test probe.
To check the condition of that circuit, we will need to repeat the tests with the alternator running.
These are just examples. Also your circuits are different. Sketch out what you've done and then you can come up with tests to narrow the areas to look in. Sometimes its just as easy to take connectors off and do visual checks first.