1968 Ford Pick-up

1968 FORD F-100
68,000 MILES • V8 • 2WD • AUTOMATIC
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SMOOTHLUV
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  • 1 POST
I replaced my alternator and voltage regulator brand new, and I cannot get my truck to run off the alternator, it only runs on the battery, every time I discconect the positive from the battery my truck dies. Can you please help me?
Mar 22, 2011 at 10:04 PM
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RASMATAZ
  • ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
Disconnect the voltage regulator and jumper A to F on the connector if it starts charging -replace the regulator
Mar 23, 2011 at 12:13 AM
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CARADIODOC
  • ASE Certified Mechanic
  • 34,321 POSTS
  • ASE Certified Mechanic
Removing the battery cable is a REAL bad idea on newer vehicles with computers because if the generator is working, the excessive voltage can destroy them. You won't have any trouble on a '68 model, but there's a better test. Use an inexpensive digital voltmeter to measure battery voltage while the engine is running. It should measure between 13.75 and 14.75 volts. If it stays near 12.0 to 12.6 volts suspect the generator or voltage regulator. I have to do this from memory: If there are four wires on the voltage regulator, look for terminals "A" and "F". I think those are on the two ends of the connector but look for those letters to be sure. Remove the plug, then use a piece of wire to connect those two terminals. If the voltage goes up, replace the regulator. If there is no change, suspect the generator.
Mar 23, 2011 at 12:17 AM
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CJ MEDEVAC
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  • ASE Certified Mechanic
Many times on a Ford, the connector for the Voltage Regulator gets sorta bent or warped. Insure the contacts are clean (pencil eraser may help) and making contact.--The Medic
Mar 23, 2011 at 1:41 AM
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