How to hook up Ammeter?
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How to hook up Ammeter?
I recently found a GT instrument cluster for my 1972 Ranchero. It has an ammeter in the cluster. On the back of the ammeter, it has two wires coming out: A yellow one and a red one. Does anyone know where I hook these up? thanks
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Ford ammeters are not really ammeters like you would normally think. They are very sensitive voltmeters that read the voltage drop across whats called a shunt.
This shunt is a calibrated resistance that is in the wiring from the alternator to the battery. The wires from your ammeter were connected on either side of the shunt. As current flows out of the alternator, it builds a tiny voltage across the shunt, which makes the dash ammeter read.
You will need to find a car that had the ammeter originally. I would guess that any car or truck with an ammeter would work, assuming Ford always designed their ammeters the same(we all know what happens when you assume something). I would unwrap the wiring from the alt on a car or truck in the junkyard till you find something in the wiring that looks like a shunt. To tell you the truth, I have only seen them in drawings and industrial applications, but it should look strange since it will be one wire passing through with two little wires tapping off of it on either side. Cut this out of the junkyard car and splice it in yours, or better yet take the whole wire from the alt to the factory splice, and put it in your car.
This shunt is a calibrated resistance that is in the wiring from the alternator to the battery. The wires from your ammeter were connected on either side of the shunt. As current flows out of the alternator, it builds a tiny voltage across the shunt, which makes the dash ammeter read.
You will need to find a car that had the ammeter originally. I would guess that any car or truck with an ammeter would work, assuming Ford always designed their ammeters the same(we all know what happens when you assume something). I would unwrap the wiring from the alt on a car or truck in the junkyard till you find something in the wiring that looks like a shunt. To tell you the truth, I have only seen them in drawings and industrial applications, but it should look strange since it will be one wire passing through with two little wires tapping off of it on either side. Cut this out of the junkyard car and splice it in yours, or better yet take the whole wire from the alt to the factory splice, and put it in your car.
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The other main thing to know is that a voltmeter, ultimately, is connected ACROSS the battery, one side to positive and the other side to negative. An ammeter on the other hand, is connected in line with the positive side so that current passes through it. Ammeters read current which is expressed as amperes, voltmeters read volts which is the electrial systems "pressure".
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