Ammeter Always Showing Charge

[yusef]

Hi folks,

Interesting issue. My ammeter is always showing positive charge, even with the car off, and under load, i.e., lights on, it goes to the positive side. The same happens when the vehicle is running. All electrical is fine on vehicle. The original, rebuilt, alternator is charging, as well.

Could the voltage regulator be shot?

Thanks,
Joseph

[Habitat.pat]

Sounds like you might have a defective ammeter. Disconnect the battery &, with the engine off, it should be in the center. If it isn’t, the ammeter is defective.

If it is, has any electrical work been done since it started showing charge all the time?

What year?

Peace, Pat

[DAC21]

How long has this been going on? If it has been going on for a while you would have either a dead or over charged. bulging, (really to blow) battery
if it was the VR. Is the battery condition OK as best you can tell? I think Pat is right, probably your gauge.

[yusef]

It's a Datsun 2000, 1969. Electrical work has just been cleaning up the contacts and new (original) fuse box. This issue has been going on for a while. Note, the gauge does read zero with the car off, but as soon as I turn on the lights, it moves toward the positive, almost to the +30.

[Habitat.pat]

Ok, that’s different from your initial post, it said that it showed charge with the engine off.

Try these tests:
With the car off, turn on the headlights. Which way does it move?

Leave the lights on for a few minutes to slightly discharge the battery, then turn them off & start the car. Which way does it move?

If it moves towards charge in the first test & discharge in the second, the ammeter worsted reversed.

If they both move towards charge, the ammeter is wired wiring is not correct. Download a copy of the correct wiring diagram from the tech wiki & I’ll walk you through troubleshooting it.

Peace, Pat

[yusef]

Copy, I'll try the test and report back. Thanks!

[Habitat.pat]

I need to proofread my posts!

If it moves towards charge on the first test & discharge on the second, the ammeter wires are reversed.

If it moves towards charge in both tests, the ammeter is not wired into the correct circuit. Download the wiring diagram from the tech wiki. I can help straighten this out.

Peace, Pat

[redroadster]

If it's charging amps while off ,you've got a million $ car

[23yrRebuild]

So do I....I replied to the wrong post,...sorry
Mike

[sfdaugherty]

I just recently changed a dash and found that the large white wire with the red stripe goes to the “top” terminal which is marked with a “-“ (negative sign). The large solid white wire goes to the bottom terminal with the “+” sign. You probably can’t read the marks when it’s installed in the dash so I gave the position.

Shannon

[yusef]

Okay, I tried what was described, namely, turn the lights on with car off, let it sit for a while. Result is it goes positive (near +30 amps) with headlights switched pulled all the way out, i.e., headlights on. I started the car and it will go back +30 amps with headlights on.

I suspect I've miss wired the amp meter, but also likely have corrosion somewhere because it doesn't seem like it should be going that high or low if wired, correctly.

Thoughts?

Anyway, I got distracted with another issue on the car, that I'll look post about in a second.

[Habitat.pat]

That’s what I thought. The 2 wires on the ammeter should be much larger than any other ones behind the dash. As Shannon said, the top terminal on the ammeter should be white with a red stripe & the lower terminal should be white, one on each terminal. The other end of the white wire should connect to the large stud on the starter. The other end of the white/red connects to the alternator output & the fuse box. Verify that these wires are correct & that the wiring of the fuse box is correct.

Depending on when you reply back, I may not be able to reply for a day or so, I’m heading to Ireland on vacation this week & will not be checking my email until evening & possibly not daily but I will get back to you as soon as I can.

[Curtis]

https://kendo-usa.org/datsun/datsun_das ... _69-70.pdf

[yusef]

Is the easy way to get ammeter/multi gauge via the glovebox? I don't recall how I did it years ago.

[sfdaugherty]

One thing I just remembered is that the ammeter has insulating washers on the bottom of the wiring posts. I’m not sure what would happen if they weren’t there but just something to be aware of.

Shannon