Field relay question?
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Field relay question?
I had a little electrical problem while out hunting this weekend in my 67 F-250. The original mechanical voltage regulator has been replaced with the solid state voltage regulator. Anyway the wiring harness wandered under the battery box and the field relay wire that runs from the S terminal on the voltage regulator to the ignition switch got grounded and melted the insulation off the wire. Since we were in a remote area I cut the bad section out, taped the ends and drove about 120 miles home. The drive takes about 3-1/2 hours because most of it is on crooked mountain roads.
The truck ran fine and we had no more problems. The ammeter showed neither a charge nor a discharge. It would flick a very little if I turned the headlights on. We stopped and shut the engine off a couple times and it started and the battery still is charged.
I am puzzled! What does that field relay wire do? The battery must have been charging at least partly. And the big question is did I screw up the alternator or voltage regulator by driving with the field relay disconnected?
The truck ran fine and we had no more problems. The ammeter showed neither a charge nor a discharge. It would flick a very little if I turned the headlights on. We stopped and shut the engine off a couple times and it started and the battery still is charged.
I am puzzled! What does that field relay wire do? The battery must have been charging at least partly. And the big question is did I screw up the alternator or voltage regulator by driving with the field relay disconnected?
Last edited by 67 F250; Aug 17, 2004 at 08:06 PM. Reason: Grammar
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"s" stands for stator. The s wire going from the ignition switch to the regulator brings the alternator "online". In other words, it turns the charging system on. If it stayed on all the time, it would run down the battery since it does take a little power from the battery to actually charge the battery.
The worst case senario for you would have been if it shorted out bad enough to blow out a fusible link over by the starter relay. If that had happened, you would not have been going anywhere probably.
The worst case senario for you would have been if it shorted out bad enough to blow out a fusible link over by the starter relay. If that had happened, you would not have been going anywhere probably.
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I replaced the wire and the ammeter behaves normally so it looks OK. I will test drive it tomorrow. I still don't understand how the battery stayed charged while driving for 3-1/2 hours. It still had 12.5 volts. But all's well that ends well.
Thanks Dave.
Thanks Dave.
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