rear window def on-fan speed dropped

[Russell]

Noted that today at idle, fan on speed three, lights on, seat heater on that when I turned on the rear window defroster the fan speed dropped a little. Temperature about 25 degrees.

Is this a warning that something is going on such as alternator beginnning to fail? FYI, my battery is an Autozone about 2 years old

[Ross]

I wouldn't worry. All those items on at once is a big draw. At idle there is only so much the alternator can put out.

[Russell]

I wouldn't worry. All those items on at once is a big draw. At idle there is only so much the alternator can put out.

Thanks- I sort of thought so. However, I will watch.

[tim eh?]

I wouldn't worry. All those items on at once is a big draw. At idle there is only so much the alternator can put out.

that is a big draw but even at idle a charging system in top shape should still be able to handle this... last winter my car (115A alt) could handle everything (high beams, blower on 4, rear defrost, radio,...) on and still charge at 13+ volts.

the obc test #9 is so very useful for this type of thing. i am trying to ride out this winter with a similar problem and i have the obc voltmeter on ALL the time when i am driving to be sure i don't drain the battery. the rear defrost is what really kills it. i am sure my problem is in the wiring between the alt B+ terminal and the batt+ terminal... might want to look at shogun's alternator cable repair guide.