Bulkhead Instrument panel bypass.
You are fighting yourself. Adding power accessories to the ammeter is what helps tear it up, and adds to the damage done to the bulkhead connector.
Many people condemn the MAD article but you should AT LEAST READ IT because it gives a great overview and why and how this system is so bad in modern times.
here..........
Catalog
And on that page is a great simplified diagram of the primary power distrobution
This diagram is a great map of the main failure points, just follow the "road." The fuse link can fail..........the bulkhead connector terminals (any of them, but especially the big red and big black)...........the ammeter wire terminals can fail, the ammeter itself can fail.......and RARE but there has been about a dozen cases I'm aware of that the WELDED SPLICE has failed
Now "in theory" everything should be "run" by the alternator, BUT IT DOESN'T happen that way, because 'back in the day' many of those alternators SAGGED at night, at low speed, at idle. So you are sitting there at a light, wherever, at idle, with the headlights on, your foot on the brake, the radio/ stereo on, the wipers on, the heater on. Now current is coming back through from the "battery side" through all of that to the welded splice. And the battery is discharging. Then you leave the light you are driving along. Now the alternator comes back up, current goes from the alternator (functionally not electron flow) through the black bulkhead terminal, to the welded splice to accessories. And through the ammeter, back out through the red ammeter wire and bulkhead to the battery.
40-50 years later, maybe someone added a "great big" alternator, corrosion, moisture, ........and......................................
You are fighting yourself. Adding power accessories to the ammeter is what helps tear it up, and adds to the damage done to the bulkhead connector.
Many people condemn the MAD article but you should AT LEAST READ IT because it gives a great overview and why and how this system is so bad in modern times.
here..........
Catalog
And on that page is a great simplified diagram of the primary power distrobution
This diagram is a great map of the main failure points, just follow the "road." The fuse link can fail..........the bulkhead connector terminals (any of them, but especially the big red and big black)...........the ammeter wire terminals can fail, the ammeter itself can fail.......and RARE but there has been about a dozen cases I'm aware of that the WELDED SPLICE has failed
Now "in theory" everything should be "run" by the alternator, BUT IT DOESN'T happen that way, because 'back in the day' many of those alternators SAGGED at night, at low speed, at idle. So you are sitting there at a light, wherever, at idle, with the headlights on, your foot on the brake, the radio/ stereo on, the wipers on, the heater on. Now current is coming back through from the "battery side" through all of that to the welded splice. And the battery is discharging. Then you leave the light you are driving along. Now the alternator comes back up, current goes from the alternator (functionally not electron flow) through the black bulkhead terminal, to the welded splice to accessories. And through the ammeter, back out through the red ammeter wire and bulkhead to the battery.
40-50 years later, maybe someone added a "great big" alternator, corrosion, moisture, ........and......................................