Alternator light and ABS light both came on

[whiteNSXs]

Hi gang,
Got a dilemma. I had a bad battery on the NSX and I did not have time to change it. Last week I tried to start the car, it cranked weakly and did struggle to fire up. Both the ABS and alternator came on. Later that day, I put a brand new battery in it and both lights stay on. I gave the car to my mechanic and he assumed that the alternator was bad. After taking out the alternator and gave to the local rebuilder, the alternator guy told him that the alternator worked fine on his bench. Now I have a working alternator which does not charge the battery at the other end. What could be wrong? I need more than my tiny brain.
Thanks,
Steve

 

[drew]

I just got through all this, my charging system went nuts due to a bad battery (intermittent internal short. gawd what fun.)

The NSX alternator light goes through a control box (next to inside fuse box), the ALB and something else.


Check the fuses in the inside and engine boxes.

If your idle voltage (no load) is ~14.xV then you are fine, measure against the B terminal to ground or the battery .


The alternator has 5 wires:
B - output to battery, big black wire on top of alternator.
S - Senses battery voltage
IG - Ignition switch signal turns regulator ON
L - Grounds warning lamp
? - phase time for ECU (have no idea what this does)

Drew

/ http://autoshop101.com/trainmodules/alternator/alt108.html

 

[enkrypt3d]

There's an alternator light??

 

[whiteNSXs]

So the problem was a terminal in the fuse box in the engine compartment behind the driver's seat. In whatever way happened, the jump start terminal burned out while the car was cranking with a weak battery.
Steve

 

[drew]

Interesting. The B terminal on my alternator burned up (ash, all the plating gone) and had a insulating layer of soot. Therefore, it made no contact with the battery and allowed it to discharge completely on the ride home.

I began replacing alternators, regulators and tracking down phantom problems. After 3 weeks of down time it APPEARED to be a bad battery that was shorting itself out, I replaced it and everything was great (except I had gone through three alternators, four regulators and hours of diagnosis. Turns out my original alternator was just fine and I returned it back to service).

Drew