Re: Ammeter Replacement 66 coupe
If you consider most amperage meters capable of carrying 30A the wires would be about 10 gauge or possible larger depending on length. The wires are very small on the Corvette gauge because the gauge is a Milli-amp gauge and is set up as a shunt. It only measures a very small part of the current going through a much larger wire. Like Donald mentioned in his prior post it is likely a very small resistance in one of the wiring connections that is keeping your gage from working correctly. I just use the head lights for the load. One should be able to see the gauge deflection with the headlights on and the car not running. Also mentioned there will be 12 volts at both wires connected to the gauge. If you trace this wire out you will find it is connected to a large wire with 4 to 6 feet between the two gauge connection points. Every connection has to be perfect. The resistance is difficult to measure with an ohm meter because it is so small. It will likely be best to use the voltage drop method to find the bad connection. Once while attempting to repair a gauge reading I traced it the back connection to a inline fuse. It this case (70 Chev pickup). GM used a inline fuse that was part of the wiring harness. The wire came out to the fuse and then returned to the harness. The fuse required replacement because the factory fuse was in a rubber encapsulation and was rusty. I replaced the fuse with the only type of aftermarket fuse I could find, the cheap ones that clam shell shut. I was confident I had repaired the circuit. It failed to work with the replacement fuse. I was stumped till I pulled the brand-new fuse and used sandpaper to clean the contacts and greased them up and reinserted the fuse. Then and only then did the gauge begin to work. This should give you an idea how important each connection is in this circuit. Any repaired connections have to be soldered to be of any use on this circuit.
I believe the systems sensitivity to even the slightest change in resistance is why manufactures abandoned this style gauge and went to voltage.
If you consider most amperage meters capable of carrying 30A the wires would be about 10 gauge or possible larger depending on length. The wires are very small on the Corvette gauge because the gauge is a Milli-amp gauge and is set up as a shunt. It only measures a very small part of the current going through a much larger wire. Like Donald mentioned in his prior post it is likely a very small resistance in one of the wiring connections that is keeping your gage from working correctly. I just use the head lights for the load. One should be able to see the gauge deflection with the headlights on and the car not running. Also mentioned there will be 12 volts at both wires connected to the gauge. If you trace this wire out you will find it is connected to a large wire with 4 to 6 feet between the two gauge connection points. Every connection has to be perfect. The resistance is difficult to measure with an ohm meter because it is so small. It will likely be best to use the voltage drop method to find the bad connection. Once while attempting to repair a gauge reading I traced it the back connection to a inline fuse. It this case (70 Chev pickup). GM used a inline fuse that was part of the wiring harness. The wire came out to the fuse and then returned to the harness. The fuse required replacement because the factory fuse was in a rubber encapsulation and was rusty. I replaced the fuse with the only type of aftermarket fuse I could find, the cheap ones that clam shell shut. I was confident I had repaired the circuit. It failed to work with the replacement fuse. I was stumped till I pulled the brand-new fuse and used sandpaper to clean the contacts and greased them up and reinserted the fuse. Then and only then did the gauge begin to work. This should give you an idea how important each connection is in this circuit. Any repaired connections have to be soldered to be of any use on this circuit.
I believe the systems sensitivity to even the slightest change in resistance is why manufactures abandoned this style gauge and went to voltage.
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