Im having problems with the charging system in my 67 F-100 with 352. A little quick history, the truck ran fine, it sat for 2 weeks and the battery went dead. The battery wouldnt charge so I had the alternator checked and it was bad. I replaced the alternator and regulator. The new alternator is good, I had it checked. Hooked everything up and it wont charge. I tested the output of the alternator at the battery with my voltmeter after I jumped it and it starts out at around 13.5 but steadily drops to below 10 volts. I unplugged the regulator and it still didnt charge. All the wires were fine except for the ground wire from the alternator, which is in bad shape. I didnt see any fusible links. The alternator is hooked up correctly as far as I know, battery, field and ground. The two yellow wires from the regulator plug are hot, about 13 volts, I dont know if that means anything. I have a couple of pictures if some one wants to see the wires. Im sorry I know this topic has been beat to death but Im at a loss and I checked everything I found from searching.

 

ya know there has been once or twice where i've bought something brand new and it was broke or complete crapola or both, its rare, but maybe that happened to you?
hows all your grounds?

 

The new alternator tested good and it still doesnt charge with the regulator unplugged. The ground wire for the alternator is chewed up so Im going to replace that. The engine didnt have any other ground wires other than the alternator and the battery

 

Try bypassing your amp gauge in the wiring harness behind your instrument panel. If your amp gauge is "open" then it will not charge the battery as the voltage runs thru it from the regulator. That is why a lot of people get the pulsing headlights with the pulsing of the amp gauge (and why they do not pulse when the truck is off or when the gauges are unplugged). You can use some jumper wire to temporarily see if that gets it charging.