It has battery voltage at post. I just rechecked the plug. The red wire is always hot. The green wire is hot when ignition is on. White wire has continuity. I did a voltage drop test on the thick wire that goes back to the solenoid. Meter reads .1 White wire is dead/ no voltage when running
Not sure how to full field a 3G Ford alternator. Is it as easy as grounding the bolt on the regulator that says "ground here to test"? Kind of a dumb question but just want to be sure before I blow something up So if I fill field it and it charges, does that mean the regulator is no good? Could a bad battery/ shorted cell pop a regulator on start up? I can't see how the battery is no good. It's not that old and a motorcraft.
Easier said than done. I can't get to the back of the alternator when installed. I'll have to remove it and install a solder less eyelet on the screw with a pigtail. My motivation to remove the alternator for the 26th time isn't there at the moment. Lol So what will that test prove?
It will determine if the alternator is working or not, by eliminating the regulator. If it is charging when full fielded, either the regulator is bad or the wiring is bad. Test voltage at alt output post. If voltage doesn't rise, alt is bad. If voltage goes very high at alt post, test again at battery. If volts are very high at alt and no change at battery, the wire from alt to solenoid is bad (open or high resistance) . Is the wire from the alt to the solenoid on the correct post? It's a stupid question, but a possibility. Can you get a hooked pick back there to touch the ground screw and then ground the pick with a jumper wire?
Check out “South Main Auto” on You Tube, see if Eric has a video on your car/symptom. He’s SPOT ON in his diagnostics ESPECIALLY electrical!
Ok, I have some testing to do tomorrow morning. From that page, I guess I'm not the only idiot to get fooled into replacing the alternator multiple times
Identifix picked up where IATN left off. BTW, Eric @ South Main Auto had a Ford truck w/ a shiny new alternator installed on the engine in the background when he was showing the greened-out wire lol. We've all been there.
I figured it out! Corrosion under heat shrink tubing at solenoid. It was bad! The OG/LB wire looks like it has an 18ga fusible link on it. The thick B+ wire has 2 gray fusible links of unknown size. The B+ wire looks to be 6ga so I'm thinking one 12ga link to be on the safe side? Anyone know what size links they're supposed to be? Btw, I feel like an idiot. Should of checked this after the first alternator
Do you think I could run two 18ga links to protect that B+ wire? One 18ga will protect a 14ga wire. So will two 18s essentially protect a 7ga wire?
I don't know what size fuse link should be used, but the alternator probably has 130 amp output. I don't think one 12 gauge would be enough. I'm surprised the voltage at the alternator output post didn't read higher than the battery voltage.
No, the 2 gray fuse links are 12 ga each. Did you stab the wires with a pin? Definite no-no unless you know you are replacing the wires.
It is. So if those two gray wires are 12ga each, why wouldn't two 18's not be ok? The truck is fixed. It's charging and the light is out. Id honestly like to find a new alternator harness but it's obsolete
