related voltage question Eric_R_Kissell at
Wed Oct 19 17:05:32 EDT 2005

"Nick Lawrence" <nick at> wrote:

>With the lights on, A/C, rear defrost, radio,
>wipers on, sitting in rush hour traffic the
>alternator won't keep up and battery voltage
>goes down enough to kill the motor.

I had this at about 200k miles and found two problems:

1)  bad alternator brushes

2) bad radiator fan bearings

The radiator fan was pulling a lot of current when it ran but not enough to
blow any fuses or melt wiring. It was enough so that when the fan was
running the weak alternator could not keep up.  It appeared to be
associated with the AC operation because the radiator fan runs continuously
when the AC is operating. Running other things such as radio and wipers
just made it that much harder to keep up, but the radiator fan was the big
current draw.


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