1999.5 Nissan PF brake/battery lights on AFTER alternator replaced

[miamicuse]

I had the brake and battery dash lights on. Car drove fine. Searching online it seems to suggest this is a common symptom when the alternator goes bad.

Took it to a shop and they said my alternator went bad, and I had it replaced. I paid just under $400 and it was an after market not OEM.

After that the lights went away and car drove fine.

Two weeks later, the dash lights came back on again. Only this time, it was not constantly lit, it was actually blinking. I drove around some more, and it went away. I took it back to the shop where I replaced the alternator, and they checked it and said it's charging fine. It may just be "one of those things".

Another week gone by, the lights came back, and driving around some, it went away.

In thinking back, I began to see a pattern. Each time this happened (including the first time), it happened after I had the car idling for a long period of time. For example, one time I had to drop a friend off to a store and waited for him, while I had the air conditioning and radio on, the wait took a while, the other time, I was waiting to pick up my kid at summer camp and he took his time, both times I think it was a good 20 minutes or more while the car sat in PARK and I had the AC on, radio on. Then on the tail end of that the brake and battery lights came on.

The first time, the lights stayed on, and I had the alternator replaced.

The second and third time, they stayed on, and after I drove the car a bit (30 minutes) they went off. In fact, yesterday, I was watching the dash, the brake + battery lights on, I drove for about 10 minutes, then they changed from constantly lit up, to a rapid blinking, and when I stepped on the gas, the lights went off, when I let the foot off the gas pedal, the lights came back blinking, I did that for about another ten minutes then it went off for good.

Any ideas and suggestions what could caused this? A bad replacement alternator or something else? I know they replaced with an after market alternator not an OEM.

Thanks in advance.

[Rebelord]

As you said. That can be traced back to that alternator. I would check all the wiring. Make sure its all tight and not loose. Especially since you say you can duplicate it by hitting the gas then backing off. Sounds like a wire is moving with the weight shift of the truck.

Check your battery terminals. Make sure they are not all corroded and full of gunk. Old toothbrush and some coke in a plastic cup cleans it up nice n good. Dip the toothbrush in the coke and scrub.

As for when your sitting and it coming on after 20mins or so, same thing. If a wire is loose or has a bad connection, heat will make it act up.

[01Pathmaker]

With many alternators, the output is minimal at and just above idle. This tends to be especially true for low quality rebuilt or remanufactured units. Most larger or more reputable repair shops will be able to test the output throughout the rpm range (some can even give you a printout of the results). My thinking is that this may be your issue since your lights come on after being at idle for a while, with a load. For $400 you could have bought a high quality aftermarket high output unit and done the install yourself (not all that difficult).

[Rebelord]

^^^ very true. Since your in Miami like me. Try to make a stop by a harbor freight and pick a cheap volt meter. If you catch the flyer you can even get one for free.

Next time you have a chance to let it idle for a period of time. Once you see the lights go on. Pop the hood, and check your voltage. Especially with the AC on full blast, radio on etc.

 

Should have a minimum of 14.1 volts charging. If your below that, you will spark lights.