My 66 f 100 stopped charging. Changed out alt. dont think the wiring was right in the first place so following the wiring diagram . Im not getting any power at batt terminal. I am getting power at 904 wire at regulator

 

?? "Im not getting any power at batt terminal". Are you referring to the batt term of the alternator??? In a situation where there is NO AMP Gauge, the heavy wire from batt term of the alternator goes to the battery side of the starter solenoid . If there IS a Amp Gauge, and it has been added to the truck by someone and hooked up properly, that wire from alternator will go to one term of the gauge and from the other term, the wire will go to the battery side of the starter solenoid. IF YOU have an amp gauge that is factory installed, the wire to the gauge MAY go thru a loop on the back of gauge instead of terms. In all cases, engine off, the voltage at the batt and the batt term of alternator should be the same. With ALL wires hooked up (wires at regulator have a plastic connector so should be in correct positions) turning the ign key to the on position, the field term at the alternator should have voltage, possibly a little less than battery voltage when key is on. IF amp gauge with terms installed by someone, and this is very rare, only seen once in my life, the amp gauge could fail internally and no let the current thru. then check both terms of the amp gauge for power.
Cap

 

Hi Rich Thanks for the reply. I was studying the wiring then realized the 10 gauge black cable from the regulator to the starter solenoid wasnt hooked up. cleaned the terminals and hooked it up. 13.75 volts nice. I dont think the charging system was working at all in the first place. Anyway now I have a new charging system.

 

Glad you got it working.