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fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside
reply to fartness

Re: Do I need a new battery?

A little more detail. It's only happening when I hit the brake when I'm stopped.

It also has not happened yesterday or today, since it's been 70 degrees out. It's been happening when it's been 25 to 50 degrees out like it's been the past few weeks.



IllIlIlllIll
EliteData
Premium
join:2003-07-06
Hampton Bays, NY
kudos:7

then i would say the "automatic idle throttle" (if your vehicle has one) is not functioning correctly.



EGeezer
zichrona livracha
Premium
join:2002-08-04
Midwest
kudos:8
Reviews:
·Callcentric
reply to fartness

said by fartness:

A little more detail. It's only happening when I hit the brake when I'm stopped.

It's also reasonably possible (but not probable IMO) that a brake light bulb may be shorting out. Bulbs are cheap - replace both brake light bulbs and see if the problem goes away.
--
Buckle Up. It makes it harder for the aliens to suck you out of your car.


cowboyro
Premium
join:2000-10-11
Shelton, CT

said by EGeezer:

It's also reasonably possible (but not probable IMO) that a brake light bulb may be shorting out.

Then the fuse would blow.

The voltage drops when the brakes are hit and the car is stopped because:
1. The alternator produces less current at idle speed
2. The brake lights are a fairly high drain (2x25W give or take)
3. The battery is weak

It isn't impossible for the alternator to have a problem (blown diode), but that is difficult to test without proper equipment and without removing the module. It is far more likely for a 5yr old battery to be weak.