I'm going to disagree with you guys saying its all the ammeter's fault.
The ammeter is telling him exactly what is happening.
My volt meter and ammeter disagree. My volt meter reads about 14 V with a little accelerator. My ammeter reads slight discharge always a little more with lights or any electrical device on. Whats up, and please dumb it down. I know the difference between amps and volts, just don't understand why they read opposites.
The reason they can move 'opposite' is that car/truck ammeters do not show all the current.
You car has two power feeds.
One for each source of power.
1. Battery that has stored energy around 12.5 Volts
2. Alternator that can supply power regulated to roughly 14.0 Volts. It's ability to supply power at the regulated voltage increases with rpm.
Power will flow from the higher voltage source.
The ammeter is in the battery's wire to the main splice, which is also its charge line.
So,
the ammeter only shows current flowing to or from the battery.
I know it says alternator on many of ammeters. It's the probably the same logic that resulted in BATT cast into the alternators next to the output stud.
Whatever the reason, it only adds to the confusion.
Basic power supply scheme looks like this.
Now lets look at the evidence and use it to solve the problem.
ammeter never goes to charge side .. at the bulkhead the fuseable link wire from the starter relay looks pretty shabby and slightly melted at the bulkhead. Is that the one that eventually leads to the meter.
This is how the power should normally flow withthe alternator regulated to 14 Volts once the battery is recharged.
Your '70 has slightly different votlage regulation and another conector for the ignition switch, but concept is the same.
Turning on the headlights while driving causes the ammeter to show discharge.
That must mean that the easiest path from a power source to the headlights is from the battery rather than not the alternator.
Based on the bulkhead connector photos, its probably due to high resistance in the alternator output.
It would be helpful to know where the voltmeter is measuring, but this probably what is happening.
Even if the alternator is producing power at 14 Volts, once the current has made it through the connector mess, maybe its down to 13.5 Volts or less.
Voltage drops through every resistance the current the current flows through.
Where can I get the center connector to replace this.. I have a battery cutoff connected to battery.. and I use it, but want to fix this even though I don't look forward to screwing with this.. ESPECIALLY if I need to go under dash..
I've replaced connectors by looking up the part number in the service manual and then checking ebay etc.
Its also worth posting a wanted request in the FABO classified. State the year, model and which connector(s).
There is foam seal inside each connector. Those can be bought from DMT
The wire terminals are probably Packard 58 aka Chrysler type, but may be Packard 56.
You'll need an open barrel crimper.
I'm taking it that the wire you need to change is from the relay directly to the ammeter, and eliminate that wire from the bulkhead, using a fuseable link in the circuit. To eliminate the ammeter do you join the three wires ( two ammeter and the new hot wire ?). Or am I starting a fire.
You might be.
Important points.
Protect everything downstream of the battery with a 16 gage fusible link.
Fix the bulkhead connector, especially the alternator output and the 'ignition wire'. The ignition wire also feeds the voltage regulator. If it sees the wrong voltage (due to resistance in the connectors) it doesn't know that.
You
can run a parallel alternator output wire to the ammeter stud closest to the fusible link.
- use good ring terminals, insulated would be best.
- use a good grommet
All of these power circuit wires are always connected to the battery. Touch any one of them to ground and the battery will discharge. ('til the fusible link melts)
The problem is almost certainly in the alternator output wire.
Based on the evidence so far, the battery power feed/charge line is the one in better condition!
