I have replaced the battery & alternator 3 times & it works for a while then the alternator goes bad agian

The battery needs to be replaced or the alternator is bad. I would try to replace the battery in your car first to see if that fixes the problem. If our car is still not starting up or if the battery keeps on needing to be recharge then the alternator is bad and should be replaced.

First check alternator charging rate , with engine running check voltage at battery should be 14 volts + or - .3 volts if ok check for light staying on in trunk or glove box .

How old is the battery?

How many times has it run down?

I would say the battery is shot & your loosing
PCM Module Voltage & the car goes down

Is the alternator working?

Only proper testing will answer that
Replacing parts is never a fix for anything
Have to see the circuits on a wiring diagram
& know what to test & how
What your suggesting is the alternator is not turning
on or staying on,so either the newest one is bad or
the ignition sw or other item in the control circuit to
voltage regulator fail to work properly.
Also a bad battery may not take & hold a charge or the
cables are corroded inside,many things that should have
been eliminated long time ago with the new alt going on

This is easy to test but you need a multimeter. Connect the multimeter to the battery and run the engine at a fast idle (say 2000 rpm). You should get a voltage reading anywhere from 14 to 15 volts if the battery is fully charged and the alternator is working. If the reading is around 12 volts, then the alternator is not working.

Are you talking about fuse # 15 in the Power Distribution Center under the hood? The 70 Amp fuse?

There are only a few things that can make this fuse blow:

1. The battery is installed backwards
2. There is a short to ground in the alternator or the battery cable that goes to the alternator
3. A defective/shorted Electrical Load Detector Unit (ELD)

I guess you have allready found out, so I don't need to preach to you about how replacing a fuse without FINDING and CORRECTING the REASON it blew, will only cause another innocent little fuse to have to give up its life to keep your vehicle from burning to the ground!

Its possible the alternator that was installed is defective. If you have a six cylinder check for power at the positive post on the back of the alternator. If you see battery voltage than I would suspect the alternator is bad.

BTW, you had the serpentine belt replaced as there is no timing belt on either of the motor options for that vehicle.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

REPLACE BATTERY CABLES SEE WHAT HAPPENS.YOUR BATTERY CABLES IS OLD HAVE A LOTS OF RESISTANCE IN THEM.MAKE SURE YOUR GETTING THE RIGHT AMP ALTERNATOR.BECAUSE A LOWER AMP ALTERNATOR WILL OVER WORK TRYING TO KEEP BATTERY CHARGE THAT WILL SHORTING ITS LIFE.CALL CHEVROLET DEALERSHIP PARTS DEPARTMENT ASK THEM LOOK UP WHAT AMP ALTERNATOR YOUR VAN USES MORE LIKELY 105 AMPS.

your alternator is defective......have it checked for current output when it's loaded...all accessories on....alternators should put out about 100 amps as an average but it also depends on the state of the battery......the battery actually powers the alternator for the alternator to recharge the battery, so if the battery is bad, it will load down the alternator and possibly damage the regulators inside it....if the alternator is bad then it might damage your new battery......one way to check is to start your car, then remove either the positive or negative cable from your battery...the car should continue to run.....hold the gas pedal down until your rpm is about 1500 and turn on your accessories....if the car dies at that rpm ...then the alternator is definately defective.....voltage output will show 14-15 volts but not enough current and current is whats required for things to work right.....good luck....., the reason for at least 1500 rpm is because alternators don't put out until a certain speed is reached so at 1500 rpm, it should be more than enough for the alternater to produce current.

check for bad or corroded or oxidized connection of all ground and positive cables of the charging system as well.......bad connections cause high resistance to current flow and severly limits current capacity.....loose connections do the same thing......it's a good idea to clean or replace these cables first then try the above.

silvio

It sounds like the alternator belt or the alternator is going bad. The squealing sound was probably the alternator belt. the alternator belt might need to get tightened or replaced or you may need a new alternator. The alternator keeps the battery charged. When the alternator goes bad the battery can not be recharged. You also should keep the power steering fluid up to par or the power steering will go bad on you.