Electrical issues

Have the battery checked at a local auto parts store. They will do it for free and this will eliminate the concern of a dead/weak battery (Of course that might just be the problem). It does sound like a bad battery.
Now, if the battery fails the test, once you get a new one, have the charging system checked to be sure that a bad alternator is not the cause of the failed battery. (They will check that for free too).

The first thing is to do is measure the battery's voltage with a digital voltmeter. It will be 12.6 volts if it is good and fully-charged. If you find closer to 12.2 volts, it is good but discharged. Charge it at a slow rate for an hour, then check it again. If you find around 11 volts, it has a shorted cell and must be replaced.

Next, measure the battery voltage again with the engine running. It must be between 13.75 and 14.75 volts. If it is low, suspect the generator. If it is okay, that means it is okay to perform the second part of the tests, but that requires a professional load tester. Your mechanic will test the full-load output current and "ripple" voltage. Since the 1987 model year, GM has had a real big problem with repeat generator failures. It is not uncommon to go through four to six generators in the life of the car. To reduce the number of repeat failures, replace the battery at the same tine unless it is less than about two years old. Due to their design, these generators develop a lot of harmful voltage spikes that can damage the internal diodes and voltage regulator, and interfere with computer sensor signals. The battery absorbs and dampens those spikes, but as it ages and the lead flakes off the plates, it loses its ability to do that.

If one of the six diodes has failed, all you will be able to get is exactly one third of the generator's maximum rated current. 30 amps from the common 90 amp generator is not enough to meet the demands of the electrical system under all conditions. The battery will have to make up the difference until it slowly runs down over days or weeks. With a failed diode, ripple voltage will be very high.

Unrelated clicking is usually caused by various relays turning on and off due to computers that are confused by low voltage. That is a secondary symptom and not really a good clue.

Besides the battery and charging system, follow the smaller positive battery wire to the under-hood fuse box and be sure that connection is clean and tight. That one causes a lot of trouble on all car brands.

It is five years old, so if you do not replace it, it is going to allow the generator to fail if that has not happened already.

You do not add stress to the generator if the battery is bad. An AC generator, (technically "alternator" is a Chrysler term since they developed it and copyrighted the term), will only produce exactly the amount of current called for by the electrical system. When the system is working properly and the battery is fully-charged, all current comes from the generator, not the battery, while the engine is running.

As far as when various lights turn on, throw all your understanding and previous experience with cars out the window. Common sense and what would appear to be normal operation is gone on today's cars thanks to all the dozens of unreliable and unnecessary computers. At ten volts we used to have dim interior lights. Today we have a Body Computer that runs those lights, and it won't turn on with low voltage, or it will do weird things. You are better off concentrating on the starting system and do not pay any attention to all the computer-controlled stuff.

12.4 volts is not fully-charged. There can be self-discharge taking place, usually from condensed acid on top of the case, but also from inside. At five years almost all the lead is flaked off the plates and it collects at the bottom of each cell. Here and there you will find a battery that lasts up to seven years, but on GM cars and trucks you are asking for a failed generator if you leave that battery in there.

CARDIODOC, very useful information there. Thanks, Johnny G

I am hung up on the corrosion!

Look my link over/ pictures at the end!

https://www.2carpros.com/questions/1996-chevrolet-tahoe-wont-start-sounds-dead-battery-jumpbox-get-same-reults

Return with good news and a big ole grin!

The Medic

If the battery was trickle charged for 24 hours and still doesn't have enough power to crank the engine, replace the battery. After all it has "full power" when hooked up to jumper cables (which means it is getting power from the donor vehicle), but no enough when it disconnected and its 5 years old. What is the warranty on the battery?

Have battery cables been checked for internal corrosion?A continuity check will not show this condition, A voltage drop test will. Pos. Batt. Terminal to pos. Starter post with voltmeter leads in between the 2, A drop over.2-.3 is acceptable any higher not.

Please get back to us on this problem so it can help others.

Best, Ken