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Nissan truck alternator trouble

I own a 1995 Nissan King Cab truck. In the two and a half years that I have owned it I have been through three alternators. I believe that this is not normal. I seem to have problems in the electrical area with this truck. It seems to be happening around the battery/ alternator area. When the alternator goes out it happens slowly. First, through the radio, it sound like the people on it are under water a gargling sound. I have to push the gas harder to get it to go. Using the blinkers or lights makes it worse. It will run like this for a few miles then stop. I guess this is due to the alternator stopping and the engine running off the battery. I change the alternator every nine months or so. I don?t know if this helps but when listening to the radio on AM I can hear the alternator hum on it especially if the station weakens.

Check ALL grounds including the engine to chassis ground.

Remove/clean thoroughly and replace wrench tight (not finger tight) all electrical connections you can see. Do NOT forget the starter cable connections.

Do a full load test on the alternator and (fully charged) battery before and after the connection cleaning. Do this test with the alternator and battery IN the vehicle.

Check to ensure none of the fuses or relays are of the wrong amperage.

There may be something that is causing the alternator to put out a higher than normal charge. If there is a wiring problem to the regulator for instance, and the voltage the regulator sees is lower than the actual battery voltage then the regulator will try to compensate for that and boost the output. Over time that can shorten the life of the alternator.

Check the voltage across the battery while the engine is running and then check the voltage on the wires on the back side of the alternator compared to ground. The voltage on each of the wires should be close to the battery voltage. Also check the voltage between the alternator output lead and the positive battery post. There should be less than .1 volt across there.

You give info on the alternator,this is useful, what has been going on in regards to the battery?

Are you buying quality alternators? Have you changed manufacture or rebuilder of these alternators?

I had a neighbor who had a Nissan pickup that would lose the alternator every year. Since the first replacement alternator had a lifetime warrantee and he would do the replacement, he kept it up until the parts store threatened to stop supplying replacements. His alternators would fail about the first time it rained in southern California. I tried to have him let me do a postmortem on an alternator but he did not want to contaminate the warrantee. He eventually traded in the Nissan to buy a large GM pickup so I never did find an answer to the failure question. The only guess I could come up with was a current draw spike that was taking out a rectifier diode.

If you find out how your alternators are failing or what cures the problem, please post back to let us know.

I hope to hear if you found a solution -

my 97 Nissan 2 WD PU recently developed a similar set of symptoms. My battery is getting drained so much after a few hours on road trips (especially when rainy or cool/humid) that the headlights dim and the engine starts lurching as if the plugs aren’t firing correctly. When this happens, I find that I can stay on the hwy by occasionally taking my foot off the accelerator until the headlights brighten up enough to let me know I can accelerate again for awhile. And, like your 95 kingcab, the engine is much less responsive to pushing the accelerator when this is all acting up. Battery, plugs, wires etc are all good shape.