# 03 pathfinder voltage/alternator problems



## harmankardon35 (Oct 3, 2007)

Well the pathfinder died flat on the highway, no "battery light" that I recall. I thought "ok its an original battery (really) so i replaced it. Starts/runs good. Drive home no problems. Do a voltage test on the bat and its 12.6v off, but it really doesn't go any higher when running (i assumed the alt should be pushing 14v) ...if i put a huge load on the electrical system it goes to 11.9V...too low. Problem is, i got NO BATTERY LIGHT. It works, i see it turn on when i start the car, but it goes out. One thing i tried was removing the 7.5A "alt" fuse and the voltage started climbing (up over 15v) and i had a red battery light..so alternator does make power. Now im not sure if its doing its job or if im fixing to break down again.. Is the regulator outside the alternator? can it be replaced separate?

thanks for any input


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## smj999smj (Jan 1, 2006)

The regulator is inside the alternator. It's odd that you are measuring lower than spec voltage and the charging system warning light (which is apparantly working) is not illuminated. One thing you may want to do is, while running, perform a voltage drop test between the alternator "BAT" terminal (on the back of the alternator) and the positive battery cable end. The voltage should be less than 0.2 volt. If it's not, check for continuity/resistance in the circuit.


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## harmankardon35 (Oct 3, 2007)

it seems to be charging intermittently. It falls below 12, then i hear the motor go under load (rpm's fall) and the voltage rises to ~13.8, then a few seconds later it falls off again. Im not sure if this is 'normal' behavior..(momentary bump from the alternator to keep it charged?)

And through all this, NO battery warning light. The only time it comes on is if i pull the small 7.5A "alt" fuse and then the voltage climbs too high (over 14 at lease). This tells me the alt is making power, i just need to figure out what the voltage should be @ idle on an average pathfinder.


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## harmankardon35 (Oct 3, 2007)

so i got as far as removing the belt and alternator bolts...then i said forget it and put it back together. I cant get behind the alt to undo the power cable, that clip and brackt..and even if i could i dont see the alt fitting out through the bottom without moving some other stuff. 

Now i have a battery light, A/T temp light and ((!)) light that flash simultaniously..and my voltage is high (15.5v):lame:


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## smj999smj (Jan 1, 2006)

Sounds like you have a bad regulator...which means the alternator would have to be rebuilt or replaced. Regulated output specification is 14.1-14.7 volts per the FSM. The MSRP on an alternator is $414; you can find better prices on sites like 1stAAANissanParts.com. That's a lot for an alternator, but I've seen a lot of problems with aftermarket remans. If you don't want to go with a genuine Nissan part, I would recommend you get it rebuilt by a reputable auto electrician or if you must go aftermarket, go with a brand new alternator by a reputable brand name. It's not a job you want to do twice because of a bad part!


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## harmankardon35 (Oct 3, 2007)

well there's a guy in town that has been rebuilding alternators for decades...he does it well so ill bring it to him. What i really need to know is how to remove the alternator?? it doesn't seem to fit out the bottom, i found some vague posts about slipping it between fan blades and bringing it to the top, and also removing the battery + tray to remove it. Anyone done this on an 03 pathfinder?


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## IanH (Feb 11, 2003)

Any progress, haven't had to figure this out yet on my 2003.

BTW you can replace the brushes and voltage regulator if you can source the parts.
I have done that myself on a couple of cars over the years.


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## IanH (Feb 11, 2003)

looks like rock-auto has a voltage regulator / brush assembly but its $234.


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## IanH (Feb 11, 2003)

maybe a wrecker yard unit might be an OK fix ?


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## harmankardon35 (Oct 3, 2007)

i had it rebuilt, The guy in town is really sought after for his work, he runs an electric shop that's super busy. Anyway, he told me it was an unusual alternator (Mitsubishi) and every part was "unique" when he ordered it, apparently had to source from 3 different places. All said and done it was a $200 repair, and a big PITA to take out/put back in. (hint: remove the rad fan and rad fan shroud)

The series of events was weird so i think this may be of use to future readers here.

First, the pathfinder died on the highway...cold turkey, no warning lights, just dead battery. It was an original battery so it was obviously in need of replacement anyway (9 years old...should have been replaced years ago but, oh well)

New battery in, starts and runs just fine. Drive it for a day, notice the starter is a bit sluggish, check voltage and its low (~11.5v running) but no warning lights yet.

Next day Start it up and i get intermittent flashing battery, A/T temp and ((!)) lights, and these flashing warning lights also screw around with the Daytime running lights (flashing on and off constantly)

Voltage is now high ~15.5v, apparently had severe "ripple" current from fried diodes.

So let this be a warning, if you notice the engine turning over kind of sluggishly in a pathfinder, don't rely on dummy lights to tell you your battery is going to die:balls:


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## IanH (Feb 11, 2003)

I haven't had blown power diodes since 79 GM suburban.

so $200 was clearly a good price. Thanks for the "hint" !!


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## dadondada (Feb 22, 2016)

So what was the trick for getting the lock nut on the back of the alt reinstalled??


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