I have the tell-tale signs of a bad alternator: batt light, brake light & only 12.5 volts across the battery when the engine is running.
I also have a check engine light, but the Autozone code reader can't communicate with the car.
The OBD II plug doesn't seem to have any power.
(one other weird symptom, the cig lighter stopped working.

Should I just go ahead and replace the alternator or is there something else to look for?

Thanks,
Bill

 

Yes, replace the alternator. Your modules are not getting enough power. Be sure also, to inspect your battery/alt cables for corrosion.

 

I was having the same situation. Local shop determined it was the battery, which was over 5yrs old at the time. Replaced that to only have the same thing happen, lights in the dash lit up, car was stalling, just acting crazy. I had the alternator rebuilt and they replaced the battery again (for free). Two months later, on the way home in a terrible rain storm, car starts stalling, lights go apeshiat, couldn't use the a/c, wipers, lights, nothing. Barely made it to the same service shop. Took them two weeks to determine it was a short in a wire behind the dash. Craziest shiat I've ever encountered.

 

I just finished replacing the alternator. Everything seemed fine on my test drive. I took about an hour to finish, pulling it out from under the car, leaving the fans and radiator hoses in place. My only oops was breaking the frozen belt tensioner. So add $20 to the $165 alternator and I still came out $300-$500 under the repair estimates I was given. Thanks again to the Maxima forum.

 

Just to be on safer side, do check the output of alternator by hooking it under the load. Local mechanic should be able to test it. I had to replace my battery due to high volt from the alternator.

 

I had my old alternator tested at the parts store and it failed.
I them test the new one and it passed.
My Interstate battery is about 6 months old and seems fine.
I've got 200 miles on the car since the repair and everything looks good.

 

So now you might be able to run the scan tool for the check engine light

 

I'm sure the CEL was for the lack of electrical power. The CEL is probably already cleared.

 

+1
No CEL, No codes

 

So a volt meter would "prevent" this from occuring again, as in warning you and you could shut it off to prevent damage? Would the flush mount one or similar tied into the cig lighter "solve" these voltage unknowns before major problems occur?

 

That’s absolutely correct. I remember one of the member already have one installed.

 

After returning from car wash the battery & brake light lit, so after coming home I checked the volt across the battery and it was 12.70 and with the car running it was 13.4.

Sometimes the light is to just go away, so I didn’t paid much attention to it and after a week on my way back home the car just died in the middle of busy intersection creating a mess

 

how many miles does the alternator usually last?

 

thruought the forum i seen people throwing them out at 50k^^thas early

 

Mileage has nothing to do with alternator life. You could have a alternator go out with 1000 miles on it, and others 100000.

I still got my original and got 85k on the odometer.

 

i had 200K on my first alternator, and when i put my first set of subs in, well it died... and now after 33K more miles... As in today, right now, im waiting on NAPA to drop off my new one... So far with this max ive replaced the OEM starter at 232K the OEM battery at 226K, and the First Alternator at 211K... here i am right now 233K second Alt... Grrr but hey if you look past the Electircal problems, shes been 100% reliable over the past 40K!