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My Alternator Gauge

RagTop

RagTop

Old Grumpy
I have experience with two 1969 Mustangs that have the non-tach dash. Both have an "ALTERNATOR" gauge on the far left side of the dash. These two cars have been in the family for over 30 years. One is a convertible with a 302 and the other is a SportsRoof with a 351W. In all those thirty years I have never seen either of the "ALTERNATOR" gauges move. Both point mid gauge respectfully straight down at the floor boards. My past experience with ammeters is that they will point off to "C" when the battery is being charged and will point off toward "D" when the battery is in discharge mode supporting things like headlights, etc. My grandson left the door of my convertible open after playing in it in my garage and I didn't find it until about four days later. The battery was totally flat. No headlights, no courtesy lights, nuthin. So I called out AAA and they gave me a jump. With the car running I would have expected the needle on my "ALTENATOR" gauge to be leaning toward "C". Nope. Just pointing straight down. That was a similar experience we had with the fastback some time ago. Are these gauges functioning and I don't know how to use them or are they just useless or are both failed? BTW, both cars rolled off the line at the San Jose Assembly plant on the same day in October 1968, so maybe they both got a taste of the same crappy gauge inventory.
 
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These gauges are extraordinarily unresponsive, as they are measuring small voltage differences across two current pathways near the starter solenoid. The problem is that various connectors in between them and the gauge overwhelm the system.

You can usually get the gauges to deflect towards D about a half needle's width by doing the following:
Key to ACC
Headlights on
Doors open
cigarette lighter on
brake switch engaged
Backup lights on
 
Midlife said:
These gauges are extraordinarily unresponsive, as they are measuring small voltage differences across two current pathways near the starter solenoid. The problem is that various connectors in between them and the gauge overwhelm the system.

You can usually get the gauges to deflect towards D about a half needle's width by doing the following:
Key to ACC
Headlights on
Doors open
cigarette lighter on
brake switch engaged
Backup lights on
Click to expand...
...and fire all phaser banks. I don't remember if mine ever worked- the ammeter that is. Come to think of it, phasers would come in handy in rush hour traffic.
 
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