Alternator/Battery Question

8504 Views 7 Replies 6 Participants Last post by Nyslou, 27 d ago

swindmiller

Discussion Starter · Aug 1, 2014

I need help checking to see if my alternator is bad on my 2008 Nitro
Yesterday I left work, started just fine, and pulled in to get gas. When I went to start it after I got gas I got one click and nothing....no radio no lights nothing. I checked the battery terminals and cleaned them and re-attached and my fuse box right next to the battery had clicking sounds coming from it (relays I guess). Tried to jump it and I got lights inside but not enough to start it.
Bought a new battery and everything is fine now but I want to verify the alternator is ok and did not kill the battery. I have been having some weird noise (clicking) coming from what I thought was the AC compressor only when the AC is on and I only have the sounds when the AC is first turned on then the noise goes away...may have to replace that later.

Took my truck to Autozone to have them test the alternator. The "kid" that tested it did so with the truck off and got a message that "the voltage is too low to test". I suggested should we start it. After that he tested while it was running and the test passed.

I don't know alot about this stuff but shouldn't the truck have been running to test the alternator?

Should I test myself? I have access to a multimeter. What can I do?

The last thing I want to do is pay $175 for the alternator after I just paid $120 for the battery.....but I also don't want to break down again

Everything is running fine now but just want to make sure.

Thanks,
Scott

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meder24

· #2 · Aug 1, 2014

When I first bought my Nitro, I had the exact same issue as you. Nothing turned on however, I had the clicking noise. My battery even said that it was fully charged.
I replaced the battery and have not had a single issue since.

The Nitro is very finicky when it comes to lower than required voltages. Even if the battery showed full charge but was a little less than what the Nitro requires, it would not work.

I would say 98% that changing batteries was the fix to your issue.

And yes, without the vehicle running, the alternator cannot be tested.

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Scar0

· #3 · Aug 1, 2014

LOL at the kid that tried to test the alternator without the rig running. I would have had a word with the Manager about letting someone run a test that has no clue what they are doing...
If it tested OK after you started the rig (LOL still chuckling about that kid) then you are fine.

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swindmiller

Discussion Starter · #4 · Aug 1, 2014

Thanks...like I said I don't know much about this stuff but something seemed off

I read how to test it myself and got 12.6 volts from the battery while off and 14.3 when started so I think I'm good.
Thanks for the help!

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Blue ram

· #5 · Aug 4, 2014

Those voltages look good.
Monitor the battery when you \crank to start.
If fuse box clicks battery does not have the Juice.
Have them do a load test on battery after it sits for a while.

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swindmiller

Discussion Starter · #6 · Aug 4, 2014

Thanks..everything seems pretty good now

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Nitrogen

· #7 · Aug 4, 2014

This is from another thread.

Nitrogen said:
Hi, Could not find any more info, so i checked the voltage on my 2008 Nitro ,and the output voltage was the same as yours 14.4 - 14.5 vdc.

This is a basic rule for checking an alternator.
battery voltage 12.7 vdc
charge voltage minimum 13.7 vdc
charge voltage maximum 14.7 vdc .

Basic alternator test.
with the engine running, lets say the voltage is 14.5 vdc, turn on the headlights, the voltage should drop a little, then rise back to 14.5 vdc.
this would indicate that your charging system is good.

i hope this helps.

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Nyslou

· #8 · 27 d ago

Instarted out with the same problem. It evolved into now the battery not holding a charge, but my alternator testing okay. Was told it had something to do with the computer not telling the alternator to recharge the battery? It was years ago and I haven’t found that thread again! Keep an eye out though. I’m having to decide whether to sell my Nitro or keep. Inlove it so much

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