The ammeter on my 68 is not working, I have two wires on the plug on the gauge, one has power all the time the other never has any, key on off or car running. I took the ammeter to the bench and tried putting a battery charger through it to a battery but nothing went to the battery so I thought the ammeter was defective, then I hooked an ammeter my son had(not Corvette) to the wires in the car to try them and it did'nt work either. Any ideas, what am I doing wrong :confused:
Thanks Cole
Location: Winner of the 2006 cotter pin bending championship in Hamilton Ontario
Re: 1968 Ampmeter ???s (Cole Neadow)
Just so you know, its ammeter, not that its a big deal :p:
Ammeters have a very small internal resistance and are connected in series with the load. If you have a multimeter with an ammeter setting put it in series with your car's ammeter. If your multimeter's ammeter reads current but your car's does not you could have a bad ammeter. Although, if your car's ammeter is bad it may not allow current to flow through it at all. Does the car's ammeter have an internal fuse? Multimeter ammeters do have a fuse inside. Did you try your son's in the charger/battery circuit?
My sons ammeter did work in the charger/ battery test.
P S because I know I will get nailed by someone on my crappy spelling I even checked a parts catalog for the right spelling of ammeter, and as luck would have it I picked Riks who spells it wrong :rolleyes:
An ammeter is just an internal very low value shunt resistor (piece of tungsten wire sometimes) with a voltmeter across it. If the battery is charging but the ammeter isn't moving, the resistor is OK but the meter movement (the 'voltmeter' part) is shot. If the resistor is open, the ammeter won't move, but the battery won't charge either (since the resistor is internal to the ammeter, it can't be replaced. In either case the ammeter has to be replaced. The only other way for the ammeter to not read and the battery charge is if somebody 'jumped out' the ammeter circuit bypassing it. For example, connecting the 'Bat' terminal on the alternator directly to the battery instead of through the ammeter. If you need some diagrams to help explain this stuff, let me know. Hope this helps.
1968 Ammeter ???s
