Midlife... what fuse controls the instrument panel 70 Mustang

[3pedal 95]

Gauges aren't moving with key on...alternator gauge doesn't move with key on and lights on

[Midlife 814]

The smallest physically sized fuse (4 amp) controls the dash lamp circuitry.  There are no fuses for the gauges at all. 

Power for most gauges is from the ACC line from the ignition switch to the constant voltage regulator for oil, fuel, water.  Alternator and brake light indicators get power from either ACC or RUN-only lines, again from the ignition switch.  Ammeter gets its power from the battery and alternator.  Most times, the ammeter gauge doesn't much at all.  To test, turn on headlights, cigarette lighter, open doors (courtesy lights), stereo, and anything else that draws a lot of power.  You might see the gauge move a half needle's width. 

[3pedal 95]

Thanks,I will check further tomorrow...when I turn the key on and off  the voltage regulator clicks...is that normal...older regulator ...finned aluminum cover with out board fuse...never saw one like it ...looked perfect inside ...alternator hook up only has bat and field and ground ??...engine not running yet ...just going thru all things electric before start up from fresh engine rebuild/resurrection from the dead...all wring/connections looks good at this point....

[Midlife 814]

I don't have enough experience to tell you whether the VR clicking is expected or not.  Alternator connections for cars with ammeters have Field, Battery, and Ground connectors only.  Cars with alternator indicator lamps have the STATOR connections as well. You can't just change alternator harnesses from one system to another, as the underdash, headlight (except 1970!) and dash clusters all must match for ammeter or tach/indicator lamp.