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elec gurus help

dheavychevy38

dheavychevy38

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Ok we have a 03 2500 chevy hd with a 6.0 4x4. There is a major drain and we can't find it. The battery will be dead with in half an hour. The truck has a aftermarket stobe system and snow plow. Even if u un hook both of these just in case the battery still dies. One of the guys who is working on it said there is a 3 volt draw on it at all times. We unhooked the alt and the starter just in case and the same thing we need ideas please thanks Denny
 
Disconnect the positive battery cable.. attach a test light between it and the battery post...

if a draw is present it will light up.. pull fuses till the light goes out..that isolates the prob...
 
Ryoken is correct. And I hope your friend meant 3A draw not 3V....


Just a FYI, the lamp under the hood will draw over 2A by itself so your problem could be smaller than you think.
 
Yeah, I forgot to mention to him that you can check amp draw by using a meter instead of a testlight.... :doah: Most draws end up pulling 12v, it's how many amps that matters really...

Had a trimtab pump drawing 38 amps to spin yesterday at work... :eek1: He wondered why it was tripping breakers... :doah: :haha:
 
no light under the hood and we did the test light between the pos and the neg pulled out ever fuse and relay in or on the truck and the light never went out.
 
Well, then you need to isolate it from the battery out, till you get the draw.. more than likely start down at the starter.. pull all the leads from the main post. reattach the battery lead.. then add the next, check, next, check, etc...
 
gotcha we had the alt and the starter completely disconnected when we did the fuse and light test but we will have to try it with the meter on amps.Another advise will be great thanks for the infi guys
 
Any aftermarket stereo or video stuff in the truck?? Might want to try disconnecting that.
 
test light dont work on newer stuff to good at all for this. need amp meter to test. and it can be a pita!!!!

you have time out body modules that are timed to turn off after certion times. some i have seen can take up to 1/2 hr to time out.

dont forget also there is a door light button. need to deactivate that when pulling fuses. or dome light will get ya every time.

that truck will have 2 fuse boxes. one in truck in comon spot. also one under hood.

best find some real good info from a real shop book or take to a shop as the special order and times to let these body control thing time out can be real fun to figure out anymore.

and you said you wanted that exrta stuff till it all goes bad. :doah:
 
Chevy couldn't find the problem. The door was shut for the test. yes we pulled fuses from the inner one shut the door and waited a while because of the time issue but we only waited like 10 maybe 15 mins. We work at a shop but its a heavy eq shop mainly along with fabrication cause its for a concrete company. The main thing is i am not the greatest when it comes to wireing. I really appreciat all of the help.
 
dheavychevy38 said:
gotcha we had the alt and the starter completely disconnected when we did the fuse and light test but we will have to try it with the meter on amps.Another advise will be great thanks for the infi guys
Click to expand...

sheesh, didn't notice it was an 03..... :doah:

I'd be guessing at this point.... not sure where the main systems are picking up power, whether its down at the starter or some feed off the battery...

our older trucks, if you had the leads off the starter and alt, and still had the light going off, that'd be one funky prob cuz theres nothing else there.. :eek1: :doah: :haha: And pulling fuses wouldn't do anything, cuz you'd have no power to the fuse block...

I would still employ the same tips tho.. disconnect EVERY lead off the battery... Then start testing each for a draw to try and narrow it down...
 
ideas...

If its still drawing power enough to light a bulb or measure on the meter with ALL the fuses pulled,then its a short in the UN-fused wires,like battery cables,alternator or wires going into it,the "hot" wires the fusible links are in that go to the starter,etc..

I've used a device that "detects" shorts,thats sold at parts stores--it has a meter and a "shunt",that you wave near suspected short curcuits,like in a door panel,etc..its needle will waver,and point to the short, when it goes near the short!..another mechanic I know uses an ordinary compass to do much the same thing!--but it'll point at speaker magnets too,so if you use this trick,dont be fooled!..:crazy:
 
Ya we have come up with the following useing the method in a earlier post we came up with 1.50a when we pull the radio fuse it goes to .70a the if we pull the fuse for the info in the dash it drops to .20a but thats all we came up with. OH ya is u use your meter u can still run the power seat and other items we thought that was weird.
 
mmmm....

Couldn't understand your last post fully--but if yanking the radio fuse drops the amount of drain,its likely part of the problem curcuit..I've had ciggarette lighters drain my battery before,I'd unplug that and ensure its not partially shorted!..I think they are "hot" all the time too!(and might be fused by the radio fuse?).....

Also, I had one truck that for some strange reason,the HEI module was ' "drain" on the battery too--a test lamp would dimly glow ,until I pulled the pink wire off the HEI on the distributor cap!..there should not have been ANY juice there,with the key off!..never did figure that truck out--if I let it sit more than a week,the battery would go dead--so I took one cable off if I planned to not use it for that long,so it would start again!..:crazy:
 
The radio is going to draw a small amount, usually about around an amp or so, to keep the radio presets and stuff.
 
The problem with pulling the cable is it is a 03 chevy and is a daily driver shouldn't have to pull the cable every night it gets parked. The only 2 fuses that cause any change on the meter where the radio and icp which is the elec trip and stuff. Other than that everything else checked out ok.
 
stupid question. have you had the battery tested at a battery shop yet? might have a dead cell. or the life might just be gone in the battery. and dont buy a cheepy . get a name brand if you need a new one.
 
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