Low Battery warning light on '90 Q45

[Jerry Parks]

Installed new battery. Auto Zone checked alternator and its OK. Have I got a sensor that I need to check? Battery is being drained. Thanks!

[DAEDALUS]

Even when you rev the engine? Did you top off the battery before installing it?

[Jerry Parks]

Reving up the engine had no effect. I have two good batteries and charged both up on my charger. After I put them in the car, the light still stayed on. One of the batteries is brand new.

[Q45tech]

Bad Alternator........you would be surprised at how few people really know how to accurately test one. The alternator has 3 seperate winding each supplying 1/3 of the current. Also have seen defective alternators consume field current when shut off..........a big drain.

You need to find some to accurately test systems.

You get what you pay for at Autozone - free testing.

[DAEDALUS]

Doesn't a bad alternator light the brake and ABS leds?

[Q45tech]

Depends on what's bad in alternator the light comes on when the alternator voltage is below the battery voltage.

If one phase is out the voltage will be fine until you exceed the diminished current capacity. Why you load test the battery and alternator with a precision load computer. Necessary to observe the ripple waveform with an oscilloscope.

TOTALLY dead alternator vs partial failure in degrees.

[Jerry Parks]

The brake and ABS lights are on .. Maybe your're right.

Q56tech: Does a '87 series Maxima 90 amp alternator fit the '90 Q 45? I like to get off cheap when I can. Thanks!!

[Q45tech]

110 amperes is minimum plus the rpms vs amperes are different.

[Jerry Parks]

Q45 tech: Will a new set of alternator brushes fix my broblem?

[Jerry Parks]

Q45 tech: Will a new set of brushes fix my problem? Thanks!

[Jerry Parks]

There is a good reliable repairman in my area that replaces brushes very reasonable. I guess he should be able to check it out fir other problems. Is the Alternator fairly easy to remove on the Q? I have changed them on my Maxima and Z cars with not much effort.

[DAEDALUS]

The brake and ABS lights are on .. Maybe your're right.

Gottal give us all the info! Removal is usually a real pain, but if you've done it before on those 2 cars you'll probably be fine. It can be done with the compressor in place, but most find it much easier with the compressor unbolted and shifted slightly for more clearance. Don't put any stress on the metal compressor lines!

[Q451990]

I actually rebuilt my alternator on "Q1" once. The brushes were fine - well away from reaching the wear mark. So I just replaced the diode pack, front and rear bearings, and all was well. Then a year or so later the stator developed an intermittant short.

Moral of the story - this is enough of a pain to do that I would recommend replacing as a unit with a factory remanufactured unit. I've heard too many horror stories of problems with aftermarket units, and my own experience of rebuilding ended with mixed results.

Heath

[Jerry Parks]

Thanks Q45tech and Daedalus. You are both most helpful. I think I'll take her off tommorrow and try to determine the problem. BTW: What does a factory rebuilt alternator cost on average?

[Q451990]

Call Joe at 1-888-216-5328 for an exact quote. For some reason I can't find it on their website (http://www.everythinginfiniti.com)... the trademotion search engine that they're using is terrible. Luckily for them all of their competitors are using the same thing. My guess is $250-300.

Heath

[DAEDALUS]

I paid $235 from Joe a few years ago. Beats the local guy silly by a good $100+ (call your dealership first--you'll be shocked by the difference). You will have to pay shipping both ways to send the new one to you and to send your old one back (core charge). They'll charge you extra for the core and then credit your card when they get the old one back.