Resurrecting a 77 power wagon that's got some field wire issues. Reconstructed the harness (burnt field wire to ballast) and fired it up with a new alternator. After about ten minutes the alternator loaded so hard it began whine then slip the belt and the ballast was very hot. Any recommendations on what to investigate?
Need help troubleshooting electrical gremlin
- Thread starter Illahe
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Any idea of the charge situation of the battery? If you don't think it was down very far, the next thing is to find out what the output voltage of the alternator was. In other words, is it being controlled by the VR, or is the VR bad?
So fire it up and measure voltage at the battery. Should be no more than 14 normally, and an absolute max of say, 14.5. That itself is higher than normal
You likely made a wiring error causing the alternator to charge full tilt. The newer ISOLATED FIELD (incorrectly, "dual field") has the blue at one field connected to switched 12V power, AKA the key side of the ballast, and the other field is green, going back to the VR. VR MUST be grounded
So fire it up and measure voltage at the battery. Should be no more than 14 normally, and an absolute max of say, 14.5. That itself is higher than normal
You likely made a wiring error causing the alternator to charge full tilt. The newer ISOLATED FIELD (incorrectly, "dual field") has the blue at one field connected to switched 12V power, AKA the key side of the ballast, and the other field is green, going back to the VR. VR MUST be grounded
The battery was in the 12.5-7 range when I started the rig. It was approaching 13+ v. I do not have a ground strap on the VR as its mounted to the firewall with oem self tapping 1/4 hex heads, but I will check to make sure there is continuity with the ground. I did notice current when I hooked up the field wire, as there was a slight spark, yet my son may have had the ignition on.
Additional inspection exposed the Ignition 1 circuit "red" had gotten hot on both sides of the connecters from the steering column to the bulkhead feed.
What's puzzling me is the rig had the same failure with the previous owner. I have never seen a field wire smoked.
can you explain what isolated field means. I'm not that electrical savvy.
Additional inspection exposed the Ignition 1 circuit "red" had gotten hot on both sides of the connecters from the steering column to the bulkhead feed.
What's puzzling me is the rig had the same failure with the previous owner. I have never seen a field wire smoked.
can you explain what isolated field means. I'm not that electrical savvy.
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