I've read the FAQs on ammeter. Have also read any troubleshooting threads I can find.

My gauge points straight up all the time. Haven't seen it move.

Checked connectors - both have 12V coming in to them. Which leads me to believe wiring is good.

With ignition on both ACC and ON, I've turned headlights and brights on - would expect the needle to move toward discharge. Needle doesn't even twitch.

Based on above, I believe gauge is bad but want to check Forum to see if anyone has other ideas/tests before I order the part.

 

if you have a low amp 12 volt power source, connect the ground to one terminal and just touch the positve to the other side. It should deflect the needle either up or down. reverse the connections and it should deflect the other way. If it does that then it's good. If it doesn't move it probably needs to be re-wound.

 

I have a battery recharger that charges at 12V and can switch amps from 2 to 10 to 40.

How about 2 amp setting and touch one side of the gauge?

 

If the gauge is good, that would probably burn it out in an instant. Try doing it by touching a 1.5 volt battery first and look for movement. If you don't see any movement, then maybe move to the bigger stuff. The gauge on the '64 actually reads the differential in voltage between the starter solonoid and the accessory terminal, so both are positive, but there is a slight differential between them and that differential is the voltage that drives the gauge.

I've repaired my ammeter on my '64 and it wasn't that difficult. It has an open architecture that lets you easily get at the parts (unlike the later gauges).

As is typical, on mine the winding had burned through causing an open circuit. This was caused by prior Bubbas' work before I installed a new loom.

I simply took it apart and carefully unwound the magnetic wire, counting the number of turns as I went. It's been many years, but as I recall there aren't that many turns..., ~23.

I had magnetic wire left over from an 8th grade Science Fair project. (I'm 53 and still have that same spool around.) I don't recall if it was the same gauge, but gave it a try. I just put the same number of turns on in the same fashion and soldered the ends and put it back together. Sure enough, that fixed the gauge.

I don't know about its accuracy, but it works fine and tells you if you are charging of discharging with some relativity, and isn't that really about all you need to know?

If you want to try rebuilding it yourself, I can send you a few feet of the wire. Alternatively, there are places that can do a professional rebuild.

 

Yes, the 12V/2A source caused a rather violent needle reaction. So, I backed down first to a normal 9V square battery, then to an anemic 1.5 AA volt, which caused the needle to full swing both ways, depending on which poles I touch with the probes. So the gauge appears to be OK. So is a straight up needle that doesn't move much OK? Maybe it is and I can move onto other things.

 

Make sure that the connections are clean, especially where the harness comes through the firewall.

Mine doesn't move a lot either. It seems like it used to move a lot more before I put in the Optima Yellow Deep Cycle battery and ran a heavy gauge power line off the battery to my power amp under the passenger seat. Like I said, it reads the differential between the starter and the accessory terminal. So with the power amp on the battery, its load (or at least a portion thereof) is not realized by the gauge.

But it does move and seems to go in the direction that it should.

 

This is usually the problem area, the firewall connector.