Is there a way to test the alt. gauge?

 

With the motor off, turn on the headlights.

Does the needle deflect slightly towards D ?

 

I just checked and no movement at all. Does this mean the gauge is bad?

 

You neglected to say what year car you have the problem with so I'll do the 66. The ammeter is hooked up between the alternator and the regulator with a variety of connections any of which could be giving you an open circuit. That situation is not likelybut possible, so your first guess would be the place to start. I don't think that the gauge is reproduced or sold new by Ford so a donor car is your best bet.
Jim
And fix your signature - 'Nustang'?

 

If your car has an AMP GAUGE, the following applies:

I would say that the gauge is bad, or it is not hooked up andis bypassed. ALL of the electricity used or produced by your car (except for the starting motor) goes through the Amp Gauge. If you have a short in this circuit, you would have a fire, if you have an open here nothing will work.

In other words, if the car is wired stock:, when you turn on the headlights, use you blinker, turn on your stop lights, turn on your heater, your ignition, etc. all of the power goes through this gauge. Everything.

So I am saying that your wiring is good, lookto the gauge itself and whether it has been bypassed.

If you are running quite a bit more power through your car than stock, you might consider not using the amp gauge, and using a volt gauge instead. (big stereo, big alternator, etc.) IMO these Amp Gauges are not safe for high draw applications.

 

All the juice going thru the gauge on a 66 - no it don't.
Jim

 

Sorry it is a 68. I assumed that what ever the issue was it would be the same on all years.

 

You may be right, I made an assumption that for an amp gauge to function accuratly, everything that can charge or discharge the bettery must go through it. I therefore assumed that for the sake of accuracy, everything would go through.

Assuming that everything does not go through the gauge, the circuits that do not go through will not register on the gauge. I was assuming that the circuit was designed so that everythig exclusive of the starter motor would register on the guage.

What I can say for sure is that all of the power produced by the alternator must pass through the amp gauge, otherwise it would never show a charge. My theory is that if a person has a 100 amp alternator passing through a 40 amp amp-gauge, the circuit is overloaded and therefore dangerous. ???

You think???

 

Sounds right to me. What we need to know is what equipment do you have in that 68 that is not stock equipment.......such as a super dooper amplifier, etc.

 

Stock equipment only.