My '99 GMC Sierra has been acting up lately. The battery is original, had
it load tested and it checks out ok. If the truck sits for more than a day
than the battery is low or flat when I go to start. I verified the only
accessory that is on is my cell phone plugged into cigarette outlet. Has
anyone else experienced this? I am wondering whether it has something to do
with the cell phone or whether it is some other issue....
First check that it is charging. Use a multimeter and verify that the
battery voltage comes up to about 14 volts when the engine is running.
If that is ok you will have to deterimine if there is leakage someplace.
I would disconnect the battery lead (ground line is ok) and hook
the meter in amps mode in between the battery and line. If you have
anything more than a few milli-amperes of current you will need to try
to isolate the problem.
I would say that a 5 year old battery is always suspected.
It ma test good after charging, but with a bad cell, it will go flat
substitute a good battery and see if it is ok after setting.
or put an ammeter in series with the battery treminal and see if there is a
I'd agree with "johnny". If the truck is charging properly
and you have verified that you don't have some sort of
draw (unplug the cell phone when you turn the truck off), then
I'd go with a new battery no matter how it tests out. After
5 years, it's a bit of a crap shoot with any battery.
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