Alternator not charging?

Tiny
DODGEPODGE
  • MEMBER
  • 1994 DODGE CARAVAN
  • 3.3L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
I don't know whether this is an alternator problem or a heater blower problem. When I turn on the headlights and activate the blower motor the charging gauge drops like it is running straight off the battery? The blower motor seems to put the most drain on it?
Tuesday, October 8th, 2019 AT 8:51 AM

13 Replies

Tiny
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  • MECHANIC
  • 680 POSTS
Hi and welcome back.

It sounds like the alternator cant supply the current you need. The simplest way to deal with this is to pull it and have it tested at an auto parts store. Make sure they load test it!

Let me know what you find out.

Rich
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Tuesday, October 8th, 2019 AT 8:11 PM
Tiny
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I found out something puzzling. I started the engine and while looking at the alternator. I noticed the A/C compressor cycling on and off? How would that effect the A/C compressor? Thanks
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Wednesday, October 9th, 2019 AT 8:35 AM
Tiny
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Was your AC turned on?

Rich
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Wednesday, October 9th, 2019 AT 5:34 PM
Tiny
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No. That was definitely the first thing I checked. The switch is off but? It is still activated?
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Thursday, October 10th, 2019 AT 7:58 AM
Tiny
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Did you have defrost on? The defrost system uses the AC system to blow dry air to clear the windshield.

Rich
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Thursday, October 10th, 2019 AT 4:03 PM
Tiny
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That does not compute? Having the slide bar all the way to heat why would it be cold? Does not compute, but yes I always have to use the defrost mode. My main actuator door is broken so I use the defrost mode. It circulates the air better. Are you sure about that? I will try switching it to the heat mode and see or feel. Thanks
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Friday, October 11th, 2019 AT 8:36 AM
Tiny
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I am positive. The defrost system uses the AC system to blow moisture free air to rapidly clear a fogged up windshield. Most people dont know that if you turn your AC on and turn the temp to hot, it will blow hot air.

So we are back to testing the alternator, yes?

Rich.
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Friday, October 11th, 2019 AT 8:00 PM
Tiny
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Stay tuned. Zombie currently lacking motivation and energy.
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Monday, October 14th, 2019 AT 8:32 AM
Tiny
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  • 680 POSTS
I will be here.

Rich
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Monday, October 14th, 2019 AT 5:20 PM
Tiny
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Thanks Rich. I hope you are a patient and understanding man.
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Tuesday, October 15th, 2019 AT 10:02 AM
Tiny
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I'll assume you are? Okay tested the alternator and they said there is a bad diode. So how do I test which one is bad? Can a diode be replaced on a Nippendenso alternator? What would one bad diode cause? Thanks
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Thursday, October 17th, 2019 AT 9:00 AM
Tiny
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There are anywhere from 4 to 6 diodes in an alternator and they are on a single rail so you have to replace them all if you can find them. They run in the range of $100.00. Some you can find some you can't. If you cant you need to replace the alternator.

To look you will need to know the alternator amp rating. To get that you can get the part number off of it and call a parts store and tell them you need one and ask for the specs on it.

Rich
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Thursday, October 17th, 2019 AT 7:33 PM
Tiny
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Okay, replaced alternator with a used one. But that was before the fuel pump problem existed. Although I don't know if it quite solved the problem? Forgive me. I'm a zombie. Stay tuned.
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Friday, December 13th, 2019 AT 8:44 AM

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