Is there a way to test the alternator gauge w/o having it installed in the car?
The alternator gauge in my 67 doesn't work and I have 2 other instrument clusters laying around so I figured that there should be at least one working alternator gauge around here somewhere.
Never tried it, but you should be able to. Amp gauges are in "series" with the circuit, while volt gages are in "parallel" like most accessories.
Disconnect the positive battery post and complete the circuit by temporarily holding the amp gauge with one terminal on the positive post and the positive cable terminal on the other post.
Get someone to turn on the lights, Ignition (don't try to start the car), brake lights, Wipers, ect. One at a time. Each accessory should cause the needle to deflect a little more. If the guage is reversed (swap terminals, so the other post is touching the battery) the needle should deflect the other way.