Originally Posted by Cab_Burge
If your seeing 15 volts at the alternator stud or on the output wire and only 13.0 volts at the battery you have a bad connection( high resistance, corrosion or loose) somewhere between the two scope Two volts drop between the two is way to much tsk
take your volt meter and trace it back from the alternator to the bulkhead connector and then back on the other wire that feeds to the battery scope If your seeing 14+ volts into the bulkhead connector and less than than 14.0 volts coming out your on the way to fixing it grin
I have seen more than one Mopar, 1966 to 1971 model yrs. have the inner nut on the amp gauge loose causing what you may have now work scope
Please let us know what you find so others on here can benefit from your work also up
What year, make and model car are you working on?
Hopefully someone on here will have the correct year and model factory service manual (FSM) so they can look up the wiring schematic and tell you which wire color and pin location to test from luck



Hopefully you have it fixed. If not I agree with Cab about a voltage drop problem. If it still has problems I would do a charging system output voltage drop test next. Good luck with it. Ron