I have a 90 FLHTC. The volt meter on the dash seems low & showing a discharge. Below 12 depending whats on. The headlights, foglight, blinkers & brake put it below 12.
Just ran some checks:
Battery voltage at battery 12.51V ( year old )
Volts at battery when running 14.39
Stator output 19.3 VAC 1000rpm 39.0 VAC at 2000rpm
Stator resistance on a 200 scale was .6 ??? (Voltmeter did not have a Ohms x 1 scale)
Any ideas what is causing this issue?
Do you think its a charging issue or bad ground somewhere?
Please reply Thanks!

 

From my limited knowledge of your bike, your measurements look reasonable. The stator seems to be charging if you have north of 14 volts at the battery terminals when the bike is running. That also means the voltage regulator is probably good.
I could very well be the meter movement has become unreliable. Try to measure the voltage going to the terminals of the voltage meter and see if your digital VOM reads differently then the HD meter. That will at least tell you if it's a good or bad meter.

 

Thought I try to cleaning the ground strap from frame to motor. Still the same issues. That thing was dirty!

 

Your charging system is working perfectly, it could be a ground problem (best bet), look for corroded power and ground connections.

 

I haven't really looked, but where is the ground cable connected? Do I have to remove the seat? Battery terminals are fine.

 

More issues. Today I changed the headlamp socket. Was testing the wires to ground for high & low beam and was getting only 10.7 volts. (Ignition on, but not running) By the battery terminals, I was reading 12.6 Volts. Where am I loosing the voltage? Help!

 

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