2000 Dodge Dakota Voltage meter goes dead when restarting w

Tiny
THOMT
  • MEMBER
  • 2000 DODGE DAKOTA
  • V8
  • AWD
  • AUTOMATIC
  • 163,000 MILES
Voltage meter works properly when truck is started cold, but if I turn the truck off after the engine is warm the voltage meter goes up to 10 volts and drops back to 8 volts and the "check Gauges" light comes on. I put a multi meter on the battery as the truck is running and it shows it is normal and not discharging.
Monday, October 18th, 2010 AT 4:26 PM

6 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
How many volts are you seeing with the meter?
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Monday, October 18th, 2010 AT 8:54 PM
Tiny
THOMT
  • MEMBER
  • 4 POSTS
It was a digital multimeter and it was going from 11.5 to 12.5. I'm going to try a more stable meter tomorrow. The one I used isn't of the best quality.
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Monday, October 18th, 2010 AT 10:18 PM
Tiny
THOMT
  • MEMBER
  • 4 POSTS
Also a strange thing, the truck's volt meter was reading slightly above 14 when driving cold this morning.

Thanks in advance for anything you can share on this one.
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Monday, October 18th, 2010 AT 10:20 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
11.5 to 12.5 = no charge from the alt if the engine is running. Before you replace anything, remove the alt and have it bench tested. If I recall, the voltage regulator is an integral component in the PCM. The alt could be good with a bad PCM or opposite. Once you know if the alt is doing its job, you'll know what needs replaced.

One other thing, there are fuseable links between the alt and the battery. Make sure none of them are bad by checking for continunity.

Let me know what you find.
Joe
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Tuesday, October 19th, 2010 AT 8:50 PM
Tiny
THOMT
  • MEMBER
  • 4 POSTS
It was the alternator. It's real odd that it would work while running after starting cold. Time to pay the bill and move on.

Thanks for your ideas.
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Saturday, October 23rd, 2010 AT 12:13 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Glad that is all it was. Often times a bad alt will take out the PCM. THen it gets expensive.

Let us know if you have questions in the future.

Joe
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Saturday, October 23rd, 2010 AT 10:10 PM

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