Battery is being drained by something electrical

Alot of things. Could be a short or a bad diode in the alternator. Or even as simple as a bad relay.

ur alternator may be failin-testit--sometimes good alternators drain batt and need replacement--low batt effect the computer-kinda like low sugar in ur brain

It sounds like you have a charging problem-alternator is not recharging batt when drive, batt will only go so far before it runs out then you get your symtoms. you would need a volt meter to double check this. Fully charged batt will be about 12.7volts once car is started and running you should see about 13.8 to 14.2 volts at batt terminals if alt. is chariging batt. the other item that can cause this is the volatge regulator that controls alt. which are sometimes built-in alternator and sometimes they are external to alternator. and of course make sure your belt is turning alternator to allow it to work. One other small note if you do the engine running test-somtimes- if your car idles low(600 or 700 rpm) you need to give a little throttle (1000-1200rpm) to make sure alternator is turning fast enough for output test.

Jump start your van, with a volt meter check voltage at battery with engine running and jumper cable disconnected, you will be checking alternator out put voltage there, should have a reading of not less then 13.5 volt's, if less replace alternator, alternator is not hard to replace. two or three bolts is all that holds it in place, don't forget to disconnect battery before removing alternator.

i had the same problem on one of my cars it was the fan control module. replace that and it will fix the problem.

Have you checked the alternator? The alternator may not be charging the battery. With engine running, check the voltage at the battery (it should be ~14V). If it's less than that, your battery won't charge properly. You can take your alternator to auto store to have it load tested also to be sure. Sometime alternator issues don't show up until it gets hot. Defective alternators have also been known to drain the battery after the car has stopped.

either change the battery or the alternator,,just either of those,,,if your battery is no good it wont hold charge when started,,,also if your alternator is no good it wont charge your battery when engine is running,,,(it can also drain your battery if faulty)..get a second hand alternator in a breakers yard maybe a batt too much cheaper,,,hope i helped you,,

from your comment,theres 3 things that can cause this,loose batt.post connection,weak batt.or something in elect. circuit that stays on after car is off and drains batt.,like underhood light,dome or truck light,what u can do is when u park car unhook batt. cable,make sure batt. is well charged,hook it up next day if car starts,its something that drains batt.in car! if it doesnt start,batt. needs replacing.i ruled out starter,dealer should have checked it to see if it was pulling too much amps,and that its easy to jump.

My Answer:

Being an expert in this Electronics field this should be fairly easy.

It appears your charging system is functioning OK as you did the QUICKIE alternator/regulator test and that part appears to be fine.

Next - Never ASSUME you have a good, or NEW battery. I've seen brand new batts fail a few months after purchase for no known reason at all. Water level should be topped off esp during Hotter weather as water level will drop as the batt ages.

AND - when in doubt - Always do a hydrometer test on each cell, and make sure all cells read equally at approx 1.285 to 1.290 - indicating a fully charged batt.

When doing a LOAD TEST with an external 100 Amp Load Tester make sure you disconnect the POS terminal cable (or better yet both batt cables) on the batt before doing a good Load Test on a fully charged batt.

Batt voltage on a good fully charged batt should never drop much below 11.4 to 11.7 volts doing a 10 second load test using a Load Tester similar to say one bought at Harbor Freight Tools for like $15 when they are on sale.

If the top of the batt is wet (for whatever reason such as dew-point or leaky batt acid) this will cause the batt to self-discharge right across the top of the batt. Just like putting a small light-bulb across the batt posts and causing a drain. It happens more times than you care to know. When I worked at SEARS I seen it day in and day out......trust me I know!

Next - you'll want to check for a couple things at night, or else daylight will work as well - if you have good eyesight. You want to check and make sure your "backup lights" aren't ON when the Headlights Switch is turned OFF and the Ignition Switch is OFF as well. Sometimes a SHORTED Transmission Backup Light Switch will cause a battery drain with everything shut off. Sometimes!

Also - If you have any Interior Lights left on when the SUV doors are all closed that will surely drain the battery down.

A radio/stereo left ON will do the same as well.

A shorted tail-light (or any marker light) will also cause a battery to drain over time.

Jeeps that have a under the hood light Mercury Tilt Switch for the Engine compartment sometimes can have this switch mounting come loose and when you shut the hood the light will actually stay lit thus draining the batt down as well. Make sure you check it at NIGHT during darkness as it will show up better.

If all this proves NOT to be the cause then you will have to do an actual DVM inline amp meter test to see just how much current leakage (shorting) you have. A fuse block isolation test will next have to be done to isolate from which circuit leg the short (or current drain) is coming from.

Once that circuit is isolated then it's just a matter of finding the shorted device or shorted wire(s).

If you just added anything new electrical wise to the Jeep recently- then that is a good starting point - for if the problem wasn't there before that time, and now it is - then there is your culprit!

If you are using an external battery charging PV (Photo-voltaic) panel, and it's bad for any reason - then it will drain your battery down as well, esp if the blocking or back diode goes bad.

Also - If you have a dual battery system with a BATTERY ISOLATOR installed you might want to double check all your wiring there as well - as I've seen them go bad and cause many a battery problem!

It's gotta be something I just went over here - as I covered everything......

Let me know what it was OK?

Thx,

Frank

What initiated the need for jump starting? Is the alternator charging? Has the battery been checked?

To check the alternator, once the engine has been jumped and is running, remove one of the battery post connections. If the engine dies, the alternator is not charging the battery, and the symptoms you describe are the on-board computer going through low voltage spasms until sufficient electrical power to operate the engine / tranny is drained and the car dies.

If the car continues to run with no battery attached, the alternator is charging - - - and I would recommend removing the battery and having it checked and (if good) recharged to full capacity. I would also recommend having it charged even if the alternator is the problem just to delay the onset of the low voltage problems. The car should operate normally for a few miles before the battery drains too low after a full recharge, enabling you to get it to a shop for alternator service / replacement.

If you attempt replacing the alternator yourself, make sure the battery is disconnected prior to starting the job. Saves blowing up good stuff by accidental short.

Hope this helps and good luck!

-WB.