Alternator connector glowing red hot after jumping veh with other battery
 

My 99 Explorer had been running fine. Tonight I left my lights on, killed the battery - which is about a week old from Walmart. Boosted it with another battery I have that happens to be good. Car fired up but the connection nut with the rubber boot at the top of the alternator started glowing red hot. Obviously can't run it like that.

Any ideas what's happened? Never encountered this before.

Thanks.

Alternator connector glowing red hot after jumping veh with otherbattery
 

On 05/17/2018 01:11 AM, wrote:
> My 99 Explorer had been running fine. Tonight I left my lights on, killed the battery - which is about a week old from Walmart. Boosted it with another battery I have that happens to be good. Car fired up but the connection nut with the rubber boot at the top of the alternator started glowing red hot. Obviously can't run it like that.
>
> Any ideas what's happened? Never encountered this before.
>
> Thanks.
>
Hello, and if you're talking about the output terminal (not the field
coil terminal), then perhaps one or more of the internal alternator
diodes is/are shorted. Motor vehicle alternators are three-phase AC and
supply that to a full-wave, six-diode rectifier bridge assembly. Those
diodes can be internal or external to the alternator but most of the
time they're internal. A shorted diode or two could allow for the flow
of battery current to ground (car frame). Sincerely,

--
J. B. Wood e-mail:

Alternator connector glowing red hot after jumping veh with other battery
 

> wrote:
>My 99 Explorer had been running fine. Tonight I left my lights on, killed t=
>he battery - which is about a week old from Walmart. Boosted it with anothe=
>r battery I have that happens to be good. Car fired up but the connection n=
>ut with the rubber boot at the top of the alternator started glowing red ho=
>t. Obviously can't run it like that.
>
>Any ideas what's happened? Never encountered this before.=20

Your alternator is shorted to ground internally. Either because it got a
brief reverse polarity spike or just because it failed from age. You may
be able to get the diodes in the regulator replaced or you may have to
swap out the whole thing.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Alternator connector glowing red hot after jumping veh with other battery
 

Alternators. The weakest link in the vehicular
electrical chain.

Alternator connector glowing red hot after jumping veh with otherbattery
 

On 5/17/2018 8:55 AM, wrote:
> Alternators. The weakest link in the vehicular
> electrical chain.
>

So I can take out my fusible link then?

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

Alternator connector glowing red hot after jumping veh with otherbattery
 

In article >, AMuzi > wrote:
>On 5/17/2018 8:55 AM, wrote:
>> Alternators. The weakest link in the vehicular
>> electrical chain.
>
>So I can take out my fusible link then?

No, the alternator does that for you.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Alternator connector glowing red hot after jumping veh with other battery
 

AMuzi wrote: "
So I can take out my fusible link then?

-- "

No, wiseguy. Alternators are the most likely
underhood component to go bad in an
automotive electrical system. That's all I
was saying.

Back in college went through three new
batteries in my '81 Buick. Replaced the
alternator after that third one and never
bought a battery for that car again.