Electrical inquiry: Is my ammeter broken?

[Turtle]

So I picked up an ammeter made for a 1973 celica to run in sequence with the battery and the alternator, but I wonder if the ammeter I bought is even working?

the gauge reads from top to bottom: 50, 0, -50

In instructions i found for other ammeters, it states to see if it's working by running the headlights and the fan to see if there's an amperage draw. I did such and found that the ammeter only dips by a hair, on the scale of 0 to -50, I would say it's only -1 or -2 (amps).

I started the car and the action of kicking the starter in makes the needle jump a little. up and down in a jerking motion +5 to -5 until the car starts. then it's a steady +5 (amps) at idle. If i hit the power windows, it goes up by a hair, +6 or +7 amps. If I turn on the headlights and the fan (whilst idling at +5 amps), i can barely see how high the gauge goes up, but it does go up, like half a hair, maybe to +6 amps then goes back down to +5 amps. On the scale of 0-50, 5 amps looks very very small, the needle looks like it's very close to zero.

when I drive, the ammeter goes up by a hair, like to +6 or +7, but often goes back down to +5.

I have not yet run something electrical for more than 2 or 3 minutes with the engine off to see if the needle dips more, but i may.

so query: are these the normal workings of an ammeter?

R

[HASport AE86]

Well this is for a 4AG alternator, but it should be pretty close:

Idle to 2000rpm with no load= under 10A
Voltage should be 13.5-14.3volts (higher readings replace voltage regulator, lower readings repair alternator)

2000rpm and above with load= over 30A
A loaded system is when you have the high beams and blower motor on high while testing.
Lower than 30A reading, repair alternator. Note: A fully charged battery may result in lower than 30A readings.

[adam7]

I am facing an electrical injury with ammeter. What would be the reasons?
clamp dc ammeter

[HASport AE86]

I am facing an electrical injury with ammeter. What would be the reasons?
clamp dc ammeter

electrical injury eh? Sounds pretty serious.

[assassin10000]

Where exactly is it wired in? Positive or negative side of the battery?

[Turtle]

one wire is on the positive post of the battery, the other wire is on the alternator post. I followed the path that was shown on the very hard to read 1973 celica wiring diagrams i found online. confirmed with a better-to-read fj40 schematic. also used an autometer ammeter instruction i found online as reference.

R

[dazy5]

To get better accuracy from the clamp dc ammeter, do I have to set the panel meter to read zero when the rectifier is disconnected?
clamp dc ammeter

[assassin10000]

one wire is on the positive post of the battery, the other wire is on the alternator post. I followed the path that was shown on the very hard to read 1973 celica wiring diagrams i found online. confirmed with a better-to-read fj40 schematic. also used an autometer ammeter instruction i found online as reference.

R

Sounds like it may be bad. Ornit cant read short bursts accurately.

Andrew

[adam7]

Can we repair broken ammeter at home? What are the steps for this?
clamp dc ammeter