Brake Light Battery Discharge Warning Lights

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Chris - 23 Nov 2006 00:13 GMT

Hi Ryan,

I've created a new thread for this so that it won't be buried under
alternator belt tension.

Here's Al's explanation for this:

>If the battery/charge light is on when the engine is running, then
>almost surely the alternator output is insufficient. Eleven volts at
>40 amp load sounds a bit low but the real test of an alternator is its
>current output. I've found that a good way to test an alternator is to
>put a big ammeter (like can be found in auto stores for custom set-ups)
>in series connected to the battery ground (negative) terminal. I use a
>hefty -60 to +60 amp meter with a spare battery terminal connected to
>one of the ammeter terminals and the car battery ground (negative)cable
>connected via an old copper braided ground wire connected to the
>ammeter's other terminal. As long as you don't crank it too long and
>fry the ammeter you can watch the current flow as various loads
>(headlights, rear window heater etc.) are turned on. If the current
>goes negative as load is applied, the alternator is bad. If current
>stays around zero or slightly positive as load is applied, the
>alternator ouput is keeping up.
>
>The warning light is electrically positioned between the battery and
>the alternator so that when the alternator can output an amount of
>current equivalent to the load being asked of the battery no current
>flow goes through the light and it stays off. If the alternator cannot
>keep up with the load, battery current will flow through the light and
>it is thus illuminated. Similiarly, if the light is NOT on with the
>ignition on and the engine off, the alternator is bad due to an
>internal open circuit i.e battery current is unable to flow through the
>alternator to ground. The simultaneous illumination of the parking
>brake light and the battery/charge light is a peculuarity of Japanese
>warning lamp circuits. It means nothing and will go off when the
>alternator circuit is OK.
>
>Hope this helps and isn't too obtuse. Good luck.
>
> Al

Also, could your washing caused a short in the wiring somewhere? Did
you get the alternator, distributor cap, etc wet?

My battery discharge warning has gone away since I replaced the
alternator, BUT, the occasional Parking Brake warning comes on.
I have checked the switch at the bottom of the parking brake and that
looks fine. So there is another yet unknown reason for this brake
warning. I do have responsive brakes while on the road.

Chris

On 22 Nov 2006 11:19:32 -0800, "Ryan" <ryanclimber@hotmail.com> wrote:

>Just came across this posting and the brake light battery warning light
>problem just popped up in my 92 Toyota pickup today after washing it.
>What could be the cause of this? Up until I washed it there were no
>problems with the warning lights, they would go on when the key was
>turned on and then go offf right after.
>
>Please help.

Reply to this Message

al - 25 Nov 2006 01:35 GMT

When does the parking brake light come on? Doies it correlate with a
physical condition (e.g. moving backwards, car dead stopped etc.) or an
electrical condition (e.g. cranking, heavy electrical load etc.)?
Also, when the parking brake light comes on is it fully illuminated and
as bright as normal or is it dimmer than normal? Al

> Hi Ryan,
>
[quoted text clipped - 54 lines]
> >
> >Please help.

Reply to this Message

Ryan - 25 Nov 2006 04:34 GMT

The lights and everything seem to be fine when the warning lights come
on. They are coming on when I am accelerating and driveing at a higher
RPM. when I am slowing and coming to a stop the lights go off. I just
replaced the old battery in there and the problem went away for a day.
But returned this evening.

> When does the parking brake light come on? Doies it correlate with a
> physical condition (e.g. moving backwards, car dead stopped etc.) or an
[quoted text clipped - 59 lines]
> > >
> > >Please help.

Reply to this Message

Jarhead - 25 Nov 2006 17:51 GMT

| The lights and everything seem to be fine when the warning lights come
| on. They are coming on when I am accelerating and driveing at a higher
| RPM. when I am slowing and coming to a stop the lights go off. I just
| replaced the old battery in there and the problem went away for a day.
| But returned this evening.

Sounds like the time my alternator belt was just a little too loose. It
slipped under the conditions you describe. If your new battery was fully
charged when you put it in, that would explain why the problem went away
for a day.

Signature

Jarhead

Reply to this Message

Chris - 26 Nov 2006 00:34 GMT

Hi Ryan, Al,

In my case, where the parking light comes on intermittently, I have
found the source of the problem and have fixed it permanently.

The source was the brake fluid level in the reservoir has gone just a
touch below the MIN line mark. And so, as described by Ryan below,
the light comes on during acceleration, and goes away when slowing or
stopping. Characteristics of a switch activated by a fluid's response
to acceleration and deceleration.

Went to the store, got the Dot3 spec brake fluid, and I carefully
filled the reservoir to just a touch below the MAX line mark.

The parking brake warning light never came back on after this. Except
of course at ignition, and when the parking brake is in place.

Thanks Al for the probing questions that help this amateur down the
right corridor of auto-EM inquiry.

Chris

>The lights and everything seem to be fine when the warning lights come
>on. They are coming on when I am accelerating and driveing at a higher
[quoted text clipped - 65 lines]
>> > >
>> > >Please help.

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