Amp Guage Testing

[Richard D.]

I would like to test the ammeter guage in my car this weekend (68).

It's currently not working, and I just need to verify that it's the guage, and not the wiring, etc that's bad.

Can anyone recommend the procedure to properly test the guage?

I have a 12 volt power supply and a volt/ohmmeter.

Thanks in advance for any advise.

Rich

[Harry Sadlock]

Re: Amp Guage Testing

Rich, if it's like the amp gauge on my 63, the gauge just reveals the directional flow of current. Testing with a 12 volt power supply will probably destroy the gauge if not start a nice fire, it's toooooo much. Use a 1.5 volt flashlight battery. + to + and - to -, just quickly touch the contacts to see if you get a reaction. Then + to - and - to + to see if it give a reverse reaction. If you get nothing, might be time for a rebuild. If you get a reaction, start looking at the harness connections.

Good luck

[William V.]

Re: Amp Guage Testing

Rich

Caution

Test the guage with the ohm meter only. To test with a 12 volt power supply will burn it out. The meter works as a galvanometer shunted across a wire in the charging circuit and only carries a small amount of current. See your wiring diagram in the AIM.

[William C.]

Re: Amp Guage Testing

Follow Harry's advice and you will have a good test. Just touch the terminals with the 1.5 volt battery leads for the breifest instant to prevent damage to the coils. If the needle does not move, the meter is kaput.

[Richard D.]

Re: Amp Guage Testing

Thanks a bunch for the tips guys.

I did not get a chance to pull the guage this weekend, too many other things got in the way.

Questions though, if I have to go to a replacement for the guage, there's a bunch of options out there.

Repro - CC has on for $55.00, not returnable it seems under any circumstances.

Dr. offers a rebuild service for about $125.00.

MA has a repro one for $79.00 (I'm pretty sure that was the price).

I've read that some repros are not very accurate in their readings, etc.

Any recommendations on which way to go if I need a new one, or need to get it rebuilt (I'm pretty sure that will be the case).

Thanks a lot for any input on this.

Regards,

Rich

[Jeremy Hedges]

Re: Amp Guage Testing & reading

Wile we are on the subject, I have a '65 and what should the amp be reading when the car is at idle and/or when you are driving?

Jeremy Hedges #31711

[Wayne W.]

Re: Amp Guage Testing & reading

There is no answer to that question because it varies. In general it shows some charge until the battery is restored to normal charge and then it drops back. After everything settles down it will just show a slight charge. This could fall off at idle if the alternator is not capable or there is too much load applied. All of the readings depend on loads, speeds, battery condition, etc.

[Werner R.]

Re: Amp Guage Testing

richard
you do not have to remove the gague to test it with the 1.5 volt battery [which works well]. use those bayonet connectors [radio shack] connected to short lengths of 14 or 16 or 18 gague wire. then you can touch the battery to the bare ends of the wires and look for a gague response. the ammeter connector is easy to remove and replace if you reach under the dash, and the slip on connectors are cheap and easy to deal with.
good luck
werner