Title pretty well sums it up, alternator is only charging when it feels like it. Started happening at Winter Romp a few weeks ago. Pulled it off the trailer and the truck was running off the battery, nothing from the alternator (I have a Scangauge hooked up and I was watching voltage on it), battery light was coming on, Amigos came on, and dash lights were dimming. Drove it for a little bit and it popped back up to 14.1 volts then behaved the rest of the weekend with no hiccups, dash was clear of all warning lights. Once back in Georgia, the girlfriend drove it and the alternator failed again on her way back from an errand, battery light on the dash on top of the M+S lights. I assumed the alternator was the culprit and had it rebuilt at a local shop. They replaced bearings, brushes, and the voltage regulator, but it doesn't appear that they re-wound it. After installation, it appeared to be throwing out sufficient charging voltage (14+), but after letting the truck run for a few minutes and get to closed-loop, it dropped back under 12, again acting like the alternator wasn't putting out any voltage. I let it sit for a while and re-started, again with the same pattern of results. No battery light on the dash when I observe the voltage drop from the 14+ to the 11.9-ish reading.
Is there something dumb I'm missing? I haven't started poking around with the voltmeter yet, but I was going to start with verifying the alternator output voltage. Since it was just re-built, I wouldn't think the alternator is the culprit, but anything is possible. I've checked the connections and all seem secure. It should be noted that right before I went to Romp I installed a new starter, but that's two wires, so I can't imagine I boogered that up. Fuses all appear intact, but since it charges correctly sometimes I didn't expect to find any blown.
Is there something dumb I'm missing? I haven't started poking around with the voltmeter yet, but I was going to start with verifying the alternator output voltage. Since it was just re-built, I wouldn't think the alternator is the culprit, but anything is possible. I've checked the connections and all seem secure. It should be noted that right before I went to Romp I installed a new starter, but that's two wires, so I can't imagine I boogered that up. Fuses all appear intact, but since it charges correctly sometimes I didn't expect to find any blown.