Ammeter gone bad in Mid year ???

[Anthony S.]

Anyone ever have their Ammeter go bad, what behavior does it exhibit when it does go bad??? Thx Tony

[Mike B.]

Re: Ammeter gone bad in Mid year ???

Anthony,

I've never had an ammeter go bad. But, a few years ago my '65 would on occasion, show a discharge when idling and only center on the guage when rpms were up. After much frustration, I found the guilty party.....a loose connector at the voltage regulator. As soon as I'd push in on the multi connector under the VR, the car would again show a positive charge.
Hasn't done it for a long while. Hope it stays that way.

Without knowing your car's symptoms, I figured I'd at least tell you what mine did to me. Good luck.

Mike

[Gerard F.]

Re: Ammeter gone bad in Mid year ???

Anyone ever have their Ammeter go bad, what behavior does it exhibit when it does go bad??? Thx Tony

Tony,

There was just a recent thread on 67 ammeter problems. Turned out to be a corroded connection at the firewall harness connector.

Take a look here:

https://www.forums.ncrs.org/showthre...meter&uid=6111

[Nick M.]

Re: Ammeter gone bad in Mid year ???

Having a problem with the ammeter on my 63 also. During increased rpm's the needle does not move to the plus side but when I inroduce loads, such as turning on the lights, the needle drops to the negative side. How do I isolate whether the gauge is not working properly or the system is not charging? I've read many of the posts on the archives relating to ammeter problems however I am a bit confused by all of the various suggested testing methods. Any help very much appreciatd

[Mike B.]

Re: Ammeter gone bad in Mid year ???

Having a problem with the ammeter on my 63 also. During increased rpm's the needle does not move to the plus side but when I inroduce loads, such as turning on the lights, the needle drops to the negative side. How do I isolate whether the gauge is not working properly or the system is not charging? I've read many of the posts on the archives relating to ammeter problems however I am a bit confused by all of the various suggested testing methods. Any help very much appreciatd

Nick,

That's EXACTLY what my '65 was doing. Check all connections in the charging circuit and check your voltage regulator multi plug. Mike

[Ara G.]

Re: Ammeter gone bad in Mid year ???

Tony, Jerry gave you link to my amp problems. It was a lot of trial and error. The suggestion on using a AA battery with wire clips easily allows you to check if the gauge is bad. Use caution, as outlined in the post. Only touch the wires to the leads on the gauge for a second to discern if the needle sweeps.
My problem was, as Jerry correctly pointed out, was at the firewall connector. From memory, it was the cluster of wiring closest to the passenger side. The bad wire was the one one on the bottom on the far side column of wires. Corrosion had built up, but only on that connection. I cleaned it and the the gauge worked. Don't make the same stupid mistake I did, by leaving my battery tender on the car when I tested the gauge. It moved to the negative when I turned an accessory on, but did not move positive. THen I realized, through the expertise of the other NCRS members, that the gauge is an ameter, and not a voltage gauge. It will show differences in charge, not full charge, etc like your modern cars. When I took off the battery tender, the gauge sept positive with higher RPMs and into the negative when I turned an accessory on. Good luck. ARA

[Gerard F.]

Re: Ammeter gone bad in Mid year ???

THen I realized, through the expertise of the other NCRS members, that the gauge is an ameter, and not a voltage gauge. It will show differences in charge, not full charge, etc like your modern cars. When I took off the battery tender, the gauge sept positive with higher RPMs and into the negative when I turned an accessory on. Good luck. ARA

Ara,

The ammeter, I think is more like a voltmeter, although it measures the difference in voltage between the battery circuit and the charging circuit.
One line from the ammeter goes directly to the battery (at the starter solenoid) and the other goes to horn relay and voltage regulator.

At no load, the voltage is the same, and the gage should read zero. When it goes negative you are feeding from the battery. When it goes positive you are charging the battery or feeding the load from the alternator through voltage regulator.

So if your battery is not constantly running down, and you are showing a lot of negative on the gauge when running, and when you turn a heavy accessory on, it could be high resistance at a connection in the line running from the ammeter to the horn relay and to the voltage regulator. This would give you a false reading of the charging voltage.

However, if your battery is constantly running down, it would be a problem with the alternator or voltage regulator itself.

When you are running with higher revs and you turn your blower on high, the gauge needle should move in the positive direction. If not, I'd check out the wire from the ammeter to the horn relay, and then to the voltage regulator. On a 63, I think it is red, a 67, black with white stripe, and it goes through the firewall harness connector.