Twice in the last week I have had a really weak...almost dead battery. At first I suspected the first cold snap of the year was to blame but now I think that something is draining the battery...possible the radio or interior lights. Although they are not on per say...just the setting that when I open the door they would come on. I normally shut everything off...but in the past when I have left the radio on I have never woke up the next day with weak or dead batteries.

Could the radio possibly be draining the battery?

The batteries are almost new and the connections have all been cleaned. The only concern is that the braided rear ground is a bit grungy but the connection and stud have been cleaned and tightened.

How do I go about looking for something that is draining the batteries? Is there a starting point and process of elimination? Like check "A" then "B" then "C" could it be so simple?

Electrical Gremlins really get under my skin!!

i'm not an expert but i had bought a brand new battery and when i asked them to give it a charge up b4 leaving the store it failed the battery test. so they tried 3 more and finally the 4th passed. check with a volt meter how many volts at night and then check volts in the morning. it's doubtful a radio would drain a battery overnite but after a few days it'll drain the battery on my boat. prior experience. it could be one or more cables is not sufficiently tight. also had that problem. they need to be so tight that you cannot move the cable when tugging up or down on it. pay close attn. to the two pos cables on the battery. my problem lay there. could also be crud on the cables wicking further into areas not seen by the plastic coating on the cables.

do you have a multimeter? If you do you can set it to amps, take the ground off of the battery, touch one of the probes on the meter to the center of the negative post on the batterie. Then touch the other probe to the negative batterie cable you removed. this will tell you how many amps are being drained if any from the batterie. If you have an amp draw you can do this same test to what ever you think could be draining the batteries.

To test for current draw, you need a multimeter capable of measuring at least 20A (or so... most average multimeters can do this). Remove the key from the ignition, and tape the driver's door pin or wedge it so that you can have the door open, and not have the interior light on. Disconnect the negative cable of 1 battery, and leave it disconnected during your testing. Then disconnect the negative terminal of the other battery, and connect your meter between the negative cable and the negative terminal of the battery. You should now have a reading on the amperage that is being drawn with nothing on. If it is more than 0.5a, its too much (this is a rough number). Start pulling 1 fuse at a time until the draw goes down to a reasonable level. Once you find the offending fuse, you can determine what's connected to it and trace that to whatever is causing the draw. If you have anything aftermarket that is connected directly to the battery, that would be the first place to check. Also, trailer wiring can sometimes be an issue (especially if you have eclectric brakes). Power antennas are also a common cause (although not likely on your truck).

-Chris

Check here:.........http://dieselplace.com/forum/showthread.php?t=43521

Check here:.........http://dieselplace.com/forum/showthread.php?t=43521


Thanks for the thread reference. The spacer has already been removed from my setup.

I will get a multimeter tomorrow and try the suggestions above.

If you get a multimeter with a clamp style amperage clamp, make sure it does DC current. If you get an AC amp clamp, it will not read properly.

Sounds like ya got a dead short there, one way to see is to remove the pos battery cable, now get out your trusty 12volt test light, hook one end to the POS cable and the other end to the POS post, if it lights up you got a short, if so you got to start hunting, now to narrow your search down a little leave the light hooked up and lite, pull fuses out one at a time and when the light goes out you'll have narrowed down the seach to what ever is protected by that fuse, if no fuse makes it go out, all thats left is main wire to starter, starter itself (very rare) or some kind of add on device hooked right to the battery itself, hope this helps some.