battery dying overnight

[the_legend_1981]

my battery just started dying overnight. what can i check for draws? my truck has a 250 6 cylinder and is stock, even stock radio? It started happening right after i put a new tailight bulb in. I know nothing about electrical problems, but could this be the problem?

[ccz145a]

Is the tail light on? How old is your battery? Also check voltage with engine running, should be around 14.5V.

I think the tail light issue is coincidental, and unrelated.

[the_legend_1981]

the battery definitely isnt new. The taillight isnt staying on but i think the bulb is messed up because the glass spins inside the base of the bulb. It litereally happened 10 min after chaniging the bulb.

[HAULIN IT]

Start by removing the ground cable on the battery. Put a test light between the battery post & the cable. Make sure EVERYTHING is off, doors shut or switches disabled, ect. If the light bulb lights up, you have a draw on the system, the brighter the bulb, the larger the draw. Go to the fuse box & temporarily remove a fuse at a time until the light goes out, this is the circut with the problem. If you still have the light on after you have tried all of the fuses, the problem is with the "unfused" items, starter,headlamps, ect. At this point, start with unhooking the bulkhead connector to separate front from cab (ignition switch, ect.). With the stock radio, ect. you shouldn't have any draw, many aftermarket ones use a little to keep the memory (very dim light). You said "it happened 10 minutes after changing the bulb", I'm not following you here, you had originally said "it goes dead overnight". Explain what order this happened in & Did the battery go from good to dead in 10 minutes? Try this test & let us know, Lorne 

[Lt.Del]

You know the simple test to see if it is the new bulb in the tail light is to remove it and see what happens.  If it spins freely in the socket, I'd replace it. 

[the_legend_1981]

How high should the alternator guage read?

[ccz145a]

~14V running, ~10V cranking, 12V sitting with the key on

[choptop]

There are several things that can be causing your battery to die. It could be bad a battery, bad alternator, or some other draw. I doubt seriously that it is the bulb. Lorne gave a good test for locating a draw, you can disconnect your alternator while doing this test and see if the regulator in it is bad. But, a bad battery will kill itself over night without being connected, so disconnect the battery, and see if it dies overnight. Hooking up the battery in the morning will take just as long as boosting it, probably quicker.

[the_legend_1981]

It doesnt die overnight anymore. The alternator guage reads kind of low when running...it still charges though.  With a weak battery the guage reads much higher.

[HAULIN IT]

Tell us what you found & what it took to fix it so other's can learn from it. Lorne

[the_legend_1981]

I cleaned up the ground wire and noticed that the body ground was not hooked up...so i did that and its been good ever since.