battery or alternator.

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kingfisher73
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battery or alternator.

Postby kingfisher73 » Fri Oct 20, 2017 2:04 pm

hello all...
so over the past few days..ive been hearing the truck turn over slower for the first sec of when I turn the key..
I have no dimming lights..while driving..battery light not come on..
So today I go out and battery is dead...the gauges reads at at the ten volts mark..mayne 9.5

I'M trying to rule out the alternator..i don't have near the money needed for that....any way for me to rule out one or the other?


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disallow
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Postby disallow » Fri Oct 20, 2017 8:34 pm

Double check the battery terminals.

Over time they stretch out. I've had to get these:

https://www.princessauto.com/en/detail/ ... -p8064453e

Either that or you can replace the positive one. The negative one is part of the negative battery cable, so a little involved but not impossible.

For years before I used the shims, I used a nail.

If the connection at the battery is good, I would also suspect the alternator. Just did the one on my 05 a few weeks ago, after about 190k miles. I ended up paying someone to do it, took them about 4 hours. Its underneath and a bit of a b%&ch to get at. But not impossible.

Also, have you put a multimeter on the battery posts when the car is running? Anything lower than 13.4v would probably indicate a bad alternator.

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smj999smj
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Postby smj999smj » Fri Oct 20, 2017 9:43 pm

Well, you can replace the positive battery cable end on early R51 Pathfinders, but around 2007 or 2008, they changed the design and the positive end is not bolted on like the earlier years and a lot harder to replace.
In order to test the battery properly, it needs to be slow charged for a minimum of 8-hours and then it can be tested to see if it's good. Once the battery is known to be good and the cable connections are clean and tight, the charging system can be tested. It should charge between 13.2-15.5 volts at idle and at 3000 RPM, with loads (headlights, rear defogger, etc.) "on" and with loads "off." If not, then it is "usually" a faulty alternator, but further testing may be needed per the factory service manual as the alternator is ECM-controlled. You also need to make sure the fusible link for the alternator is good and power is getting to the "BAT" connection on the back of the alternator.

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disallow
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Postby disallow » Fri Oct 20, 2017 9:49 pm

OP has an 05, but I didn't know that about the newer ones.

I replaced it on my 05, but it was pretty stuck on there, and hard to get enough leverage to get the nut to spin off.

My fancy new code reader also has an alternator test in it. It gets you to start the engine with the lights on, then rev to 2000 rpm minimum for 20 seconds, then back to idle and turn the lights off. And somehow it looks at the voltage over that time period and determines if the alt is good or not.

It must work, as my alt failed before, then i replaced it and now it passes every time. Still hopeful I don't have a gremlin in there somewhere with all the issues I've been having lately... :(

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smj999smj
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Postby smj999smj » Fri Oct 20, 2017 10:09 pm

Yeah, the later years have the clamp built into the cable like this:

http://www.clubfrontier.org/forums/atta ... nals-2.jpg

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FLiPMaRC
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Postby FLiPMaRC » Tue Oct 24, 2017 11:39 am

I replaced mine 2 years ago with this set: https://www.amazon.com/gp/product/B01A9 ... UTF8&psc=1


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