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Old 07-04-2004, 01:43 PM   #1
AcquaCow
Scooby Guru
 
Member#: 36838
Join Date: May 2003
Chapter/Region: MAIC
Location: Reston VA
Vehicle:
2001 B50 RSTi Sedan
2011 DGM WRX hatch

Default Battery and brake lights flickering on and off together.

I searched, I found a thread on it once, now I can't find it again =P

Anyways, I've got 60k on my '00 RS now and the battery and brake lights will flicker on for just a split second every now and then. Sometimes this comes with an immediate "tick" or "bog" of the motor.

My running voltage is 15v, idle between 14.5 and 15v, car off with load on the battery (stereo on, reading voltage from capacitor) reads 12.5.

Even if running the stereo for an hour, battery won't drop below 12v with the engine off, so I assume the battery is good, so I suspect the alternator.

I also think that the voltage regulator might be toast as I see no reason for the car to ever run at 15v...

Ideas on what exactly is wrong?

Thanks,

-- Dave
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Old 07-04-2004, 01:50 PM   #2
Mulder
Trust no one
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Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 RAV4 MT
15 WRX/11 CRZ

Default

It may be one or more bad diodes in the alternator. This will not only reduce the maximum current it can produce, but the output will become "dirty" and may contain spikes that can cause irregularities in the car's electronics. It will continue to charge and the voltage readings on a meter may appear normal. The only way to confirm this type of failure is to have a shop put a scope on it, or to replace the alternator with a known good unit and see if that fixes it.
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Old 07-04-2004, 02:21 PM   #3
AcquaCow
Scooby Guru
 
Member#: 36838
Join Date: May 2003
Chapter/Region: MAIC
Location: Reston VA
Vehicle:
2001 B50 RSTi Sedan
2011 DGM WRX hatch

Default

I've got a scope...I should watch it myself =P

I have been pushing 600wrms via stereo, 1200 peak, so it's certainly possible that I've fried a few diodes...Even if I pulled all of that through a 2f cap.

Poor alt probably runs at 100% output on good night cruises with all the lights on and stereo turned up

Time to shop for a good HO alt I suppose.

-- Dave
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