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 16,8 is too high a voltage.  Your harbor freight meter might not be accurate. It is safe to assume you have another vehicle , test that one.  14.7 at the battery would be OK.  Then you can determine if your meter is off or the Pantera alt is over charging.  

   You did not say if you are still running the stock alt or you have up graded.

  A loose connection or high resistance in the alt / reg  ground circuit can cause strange voltages.  Start there rather than throwing parts / money at the problem.

   Most major auto parts stores can test the alt if removed from the car.  My gut feeling would be more likely around the regulator.  The first regulators were mechanical , the later solid state should fit without rewiring. I have no idea when Ford made the switch to solid state.

   I would expect a bad alternator to under charge  rather than over.

  If the alternator was trully bad consider a late model internal regulator in the 100 amp range. That does open the can of worms of up grade the amp meter in the center sub dash.  The amp meter handles all the current in the system and can be a fire hazard.  There should be plenty of information on this forum on that subject.

I have the same harbor freight meter as a part of my survival tool kit.  Mine  reads close to a commercial Fluke meter. I got lucky.

 The Pantera amp meter is known to bounce around alot.  That is also covered in the threads of the forum. 

  I changed gauges to Auto Meter and the amp meter is now a expanded scale volt meter.  I feel the information is more relavant.

   Still would not hurt to make sure connections are clean and secure.

   The front compartment has a stud welded to the chassis for a ground connection. The engine has a ground strap at the rear of the transaxle. The voltage regulator (stock one) is in the right rear wheel well ,  could get wet and corroded connections.  There is also a common ground stud under the dash that can be problematic. I would think the under the dash ground would affect things in the cabin and dash mostly.

   Panteras are known to have electrical problems.  This forum is a wealth of great information.

  Without starting the engine and no load I would expect more like 11.5 to 12 volt with a well charged battery. Starting the engine at curb idle the voltage should climb to 13.5 to 14.7 volt.  

  Harbor Freight also has a automotive test device that has a series of leds that show approx. voltage.    A whole $4.49.

12.7 VDC is good for just the battery

14.7  running is good, showing the alternator is charging

the swing and the lamp on . . .  not good

did you ever say if you have the original "mechanical" regulator, or a solid state, or even a built into the alternator


here is a drawing of the original charging system, showing the intial energization of the alternator field through the lamp and then the switch over to self excitation once spinning.  notice the relay that uses the center tap of the stator 3 phase windings



Images (1)
  • mceclip0
Last edited by jfb05177

my "WAG" is purely based on an acadimic view of the drawings. . .

for the intermidiant lamp,

Loose wire possible (in no particulair order)

the Y wire from starter relay to regulator A

the G/R wire from the alternator to the regulator S

there could be loose wire internal to regulator causing the voltage on the G/R wire to faulter

the transfer relay in the regulator going bad


as for the swinging output voltages. . .

this seems to be common for original as indicated by amp meter.   I really wish i was in my prime and had access to investigae this condition as it seems to be the type of problem I enjoyed solving.  my guess is it could be midigates with the addition of filtering the stepping field current generated by the mechnaical regulator.


If a solid state, then the regulator is going bad as I would assume field current stabilization is part of that design


given these are just my wild arse guesses, I will bow to any others comments


  Again good solid connections and low resistance in your grounds are important. 

  I had replaced the stock alt with a third gen Ford alt. Internal fan , internal regulator.  After 2 seasons the gen light would blink and the epanded scale volt meter would vary  about 1 volt.  Thought the regulator was failing.  Nope  regulator was a little loose on the rear of the alt case.

   At the grounds I mentioned earlier on the transaxle and front compartment I went to the hardware and bought "external tooth" lock washers . They dig into the ring terminal and stud.

   A last resort after checking all the connections would be try a different regulator.  1997 would be in the solid state era.  They are cheap at the parts store , but if you still have a bad connection somewhere it would be a waste of money.

    Again the search function on this forum should bring up a wealth of information on what other members encountered.

    Remember to work safe ,  lots of juice in the battery and working on the regulator , through the wheel well you can get squashed.

   The schematic JFB sent you came from  The Pantera Place.

   Then click on technical and there are simplified  system schematics.

    Good luck with repairs.

 Just because the engine cranks and runs does not mean you have quality grounds and connections.  More modern , computer controlled engine management systems run a ground to each sensor.  A few 10ths of 1 volt do make a difference.  

   Connections need to be clean , tight , and mechanically sound.  Wire splices and terminations need to done right.  The toothed lock washers cut into the metal , paint is not a conductor.  Silicone grease they sell at the auto parts for light bulbs is a good addition to inhibit corrosion in the future.

   I confess that I even ran a ground wire from the grounding stud on the altenator to the panel the voltage regulator was mounted on. Remember I now have the internal regulator style alternator but ground is still vital.

   I am a retire electrician .  One motto is , " If you can't fix it with a hammer, it must be elctrical."

    If electrical is a mystery there are good books on the subject.  I have several books by Tony Candella , on basic automotive wiring.  Purchased on Amazon.

    There are 2 volumes and a EFI conversion book.

Your welcome!

UFO-LOW has a good point that the battery should be in good condition and fully charged to be able to evaluate the charging system.

   Every thing JFB said is spot on and the schematics are good to see the circuit.

   The connections on the factory amp meter are known to get over heated and burnt . A peak at them is worth while. Remember to take the battery cable off when in the sub dash.  It is "hot" and not fused!

   Until you examine and repair  all the connections in the charging circuit , you might be wasting money to just throw parts at the situation.

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