• Tiny
  • 1990 Dodge Dynasty
  • 6 CYL
  • FWD
  • automatic
  • 125,000 miles

Have a 1990 Dodge Dynasty V-6.3.3 Guage on dash
registers discharge when under a load, i.E. Lights,
heater etc. Replaced battery. Still same problem.
Possible alternator?

Thanks so much
John J Burns

Do you
have the same problem?
Sunday, December 5th, 2010 AT 5:07 PM

1 Reply

  • Tiny
  • caradiodoc
  • Expert
  • 25,775 posts

Sounds like a bad diode in the alternator. When one of the six is shorted or open, you will lose very nearly two thirds of the alternator's rated output. That means you will be lucky to get 30 amps from a 90 amp alternator. A pair of headlights, not including all of the tail lights and dash lights takes over ten amps. Another ten goes to run the fuel pump and engine. Ten more amps to run the heater fan on a medium speed, and that 's all the defective alternator can handle.

Have a load test performed on the charging system. Find a shop that has a tester that can measure AC ripple. That will be very high when one diode has failed.


Was this
Sunday, December 5th, 2010 AT 5:26 PM

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