Classic/Antique Car Repair: 1968 Camaro SS convertible, 1968 camaro ss, ammeter

Question
I am helping restore a 1968 Camaro SS convertible. We are almost finished but are now working on the gauges. A set of Factory gauges were purchased and installed. All of the gauges work except the amp gauge. When installed correctly it reads charging all the time but never reads discharging. When we switched it around it reads discharging but never charging. Do you have any ideas? Thank you.

Answer
The ammmeter should show some degree of charging when the engine is running.  When the engine is off, and you turn on a heavy load like the headlights, it should show some discharge.    If this is what is happening, there is no problem.   If it doesn't show a discharge even when the engine is off, and the headlights are on, there is a problem but it isn't in the ammeter, it's in the voltage regulator, which on the external regulator cars also controls the ammeter.  

Try a new regulator, and make sure it is properly gounded.

If your car has the later style integral regulator/alternator combination, I can't even guess what the problem might be, other than the fact that it must be internal to the alternator.

Since you know that the ammeter is capable of indicating discharge, I don't believe there can be anything wrong with the instrument itself.

Dick.