Then take the battery out and charge it properly.
They put it back in and put a voltmeter across it.
If when you try to start, if if drops below 10, the battery is no good anymore.
If it starts, then rev engine slightly, and if it does not go over 14, the alternator is no good.
Then stop the engine.
Remove just one of the battery terminals.
Put a test light between the cable you just removed, and the battery post it would go to.
If it lights up bright, then you have a constant over night drain that you have to find and fix.
Pull fuses one at a time until the light goes out.
New stereos are a common cause, especially if it has an amplifier.
Most likely the battery is almost dead, and simply wont hold charge. 3 or 4 years is about average life for a bettery. When they get old, they act like yours.
Otherwise, you need a meter to see if something is draining current from the battery while it's off. If you find there is a lot of current being drawn, then pull fuses one at a time to isolate the fault.
Test between the cable and the post. read amps. you need the battery charged up and you need to know how to operate the meter. a 12v test light can be used first in case you have a large amp reading that can hurt your meter.
See how much amp draw you have, start shutting every thing off and watch the reading.
Aftermarket equipment and how it's wired like stereos and entertainment components can cause it.
But any component you have trouble with, lights that wont light or look dark in the bulb can have crossed filaments.
after everything you can eliminate, goto the relays, then the fuses, then inside, go to those fuses, you will find it eventually.
Under the hood, you can inspect connections and unplug components one by one.
Draw for KAM and radio memory should be like 200mA at the most.
The rest of your load test, starter draw, volt drops, and charging output should be done by a factory trained technician.
Take the 12 volt battery to any store that sells new ones other than Auto Zone *after you charge it up and ask for a free 15 second *battery load test. This quick test will tell you the reserve amperage capacity. Amperage spins starter motors not voltage.
A battery may "appear" to be fully charged @ 12.6 volts yet have little or no reserve amperage capacity.
First conduct a battery drain test to see if something is draining the battery overnight. Read this post on how to do it.
http://ricksfreeautorepairadvice.com/bat...
By getting a new battery, if yours does not hold a charge its done.
When I put the key in the ignition nothing happens the battery is completely toast and nothing turns and no lights come on. But once I jump the truck it runs fine. I'm just trying to find out how to stop the battery from draining over night.
