I noticed today that when I came to a stoplight the battery gauge was almost down to the red/oragne line( I think its 8 ) and the lights got dim. Then the light changed and it when back up to about 12.

I checked the connections yesturday and they where tight but the poss. side had white powder coming out of the red boot/cover thing. Could that have anything to do with it?

Also the battery is a Napa gold 60month that has Aug of 2003 punched on the sticker. So I might need a new one soon.


Later, Mike

the powder is probably corrosion, and needs to be cleaned with either coke or baking soda. Check all conections including the battery terminals, the alternator, chassis grounds, ect. If it still occurs after this, auto part stores usually will test battery'* and alternators.

12 volts is not normal. but the dash gauge is not 100% reliable. i would suggest a voltmeter reading.

1 test batt voltage at idle with nothing drawing power.

2 then test voltage with everything on. i mean anything and everythin that draws power.

you should have close to 14 volts, during both tests. a little lower during the second one, but not by much.

note* if you only read 12v, thats only battery voltage, no alternator output.

This is a bit misleading. The dash gauge has been pretty darn accurate in all the bonnevilles I've seen, driven, and ridden in.

If you read 12V in the tests above, you are NOT reading just the battery. You are reading the alternator AND the battery, as both are in the same series circuit.

I strongly suggest disconnecting the battery, and pulling the rubber boots back. Clean all the corrosion, lube generously with dielectric grease, and reassemble.

Another thing to check is that your terminals are tight, and the battery post arent stripped. I had a case where the battery screw wouldnt tighten up enough because the battery was stripped, and the voltage on startup and under load would drop.

in my 97, the dash reads around 12, sometimes lower. volt meter on the battery and the alternator both show 14+ volts. and my 92 pa is the opposite, dash is higher than voltmeter reading. which is why i recomended the voltmeter.

what i meant by the 12v was, if there is only 12v then, there is no or little alt output.

but cleaning corrosion is definitely a good thing to do regardless of charging voltage

i'm with SJ on the gauges. My car reads 12-13 on the dash, but when i put a multimeter on the battery or alt. I get 14.4 under no load or 12.9 or so under load (and i have 105A)

Sorry but this is still incorrect, what you read no matter what is the 'average' of both the alternator and the battery. Either one can go low and drag the reading down.

If all you read is 12v then one of the two have a problem and you need to turn off, disconnect the battery, charge it, and then check the voltage across the terminals. Let it sit a few hours and check it again, just to make sure it can hold a charge. If the battery is better than 12v then its probably not the cause. If the battery is less than 12v then you need to have the charging system checked. Disconnecting the battery while the engine is running is not the way to check your alternator btw.

that may be true as an average, but from my experiance, ive yet to test a running car at 12 volts and still have a good alternator.

but to the point, mike, if you have a 12v reading its best to remove the battery and alternator to have them bench tested. to isolate one at a time. (provided you dont have a corrosion issue)

hey silver, any update?