hunting down what's killing my battery.

[vortec]

my k5 is not my dd. in non-icy weather, or when i haven't been wheeling much, it sits for a week or two at a time. and invariably, it drains the battery. that is way faster than a battery naturally discharges, so i know it's probably a bad ground or short somewhere. since it's pretty nasty outside, i'd rather not spend a whole saturday hunting for it. so, are there any typical problem spots on these trucks that i should check first?

i just got a solar battery tender that seems to be helping, but imo, that's a bandaid on a broken leg. i need to find the drain and do this right.

 

[Roland_Jenkins]

Got a multimeter? If so, pull the ground cable off the battery and see how many amps you are drawing. A clock and or a computer will draw some so take that into account.

Glove box light or any pin switch such as those on the doors are common culprits.
Also the thumb wheel for the dome light dimmer switch.
A one wire alternator connected directly to the battery.

If it were me I'd start pulling fuses and checking for a draw.

 

[muddybuddy]

i used to kill batterys pretty fast. turns out it was a bad belt. once i put the new belt on (also put on a new alternator) it worked like a champ. before that i redid all my wiring, and battery cables as well.

 

[diesel4me]

few ways to check it out..

Put a test light between the battery negative cable and the negative post of the battery--if it lights up,something is drawing current...ensure all accessories are off,then pull the fuses one by one until the lamp goes out--the curcuit drawing the current will be apparent when that fuse is pulled..

If pulling fuses wont put the light out,it could be blown diodes in the alternator..even one blown one will draw current,but the altenator will still charge,though not at 100% output..also check the headlamp curcuit,as it is always "hot" and unfused,other than a curciut breaker built into the headlight switch..

One guy I know uses a compass to find short curcuits,claiming they cause a strong magnetic feild..he simply passes it over suspected wires or where he thinks a short might have occoured,and says the needle on the compass will point out the short "like a bird dog points at a pheasant"!..they sell similar "Inductive Ampmeters" that work much the same way..I use the test lamp myself,always works for me..but it does take time to find the draw sometimes--it's not always easy,since some shorts are intermittent,and dont draw current all the time..

I find improperly installed stereos,amps, and other accessories are usually the source of current draw..or old wiring harnesses..if you have a trailer hitch plug,I've seen those cause battery drain too,if the wires corrode together,or they get full of water..look there too!..

 

[azblazer]

I guess a compass would work...but a gauss gauge would be the best.

Drains can be a joy to find. A good class act dvom in between the negative....cable and the battery and start pulling fuses...
Don't forget that a fubar diode in the altenator can cause a draw when sitting. After that...start pulling connectors off of circuits following the wiring diagram as the power flows....

DW

 

[vortec]

battery charges fine after a decent drive. only goes dead from sitting for several days at a time. the battery is not very old, and i've tried 2 others that i know work in my other vehicles, and they experienced the same drain. so it' not a bad cell. since the truck in an 82, the only thing that "should" pull power while it sits in the aftermarket head unit. however, i've pulled that out, and the battery drains just as fast.

i think once the weather jumps out of the 30s (we call that cold, in texas), i'll do some checking of the things you guys mentioned. thanks.