Help testing generator output 61 econoline

Gen light came on, no output at battery, anybody know which wire to test on the generator or the voltage regulator to determine which is at fault?

I used to be able to diagnose the old alt system by jumping f+a. Or f+3 at the regulator depending on the system but I'm lost on my 61 and don't currently have a shop manual for it.

It's a factory generator with a seperate regulator

I know I could go a 1 wire alternator as I did that on my van, just looking for diagnostic help

Governer,

Thanks, so f is power from the battery right?

Then while running there should be higher than batt voltage coming out of A terminal... And the other terminal is ground?

Testing Generator output
You can bypass the voltage regulator and make the generator go to full output. Disconnect the wires at the voltage regulator and then temporary hook the field wire to the battery wire. Hook the volt meeter to the battery and bring the engine up to about 1500 rpm's. Should put out 30-35 amps and the voltage should be anywhere from 14.5 to 18 volts

Thanks for the details, the generator was not putting out, so its in my buddys shop getting rebuilt!