truck eletric drain

Any ideas on what to do about fixing my topkick it has a 2 volt drain on the battery. It goes away when the light fuse is pulled.I have disconnected the plug of wires to the light switch and clearance plus dash plus backup plus directional signals and the drain is still there.I have allso pulled the radio plugs.

check the bulb in the glove box and center console if so equipped. not uncommon for the glove box switch to stay on, causing the battery drain.

Its a 94 and i think there are no bulbs there.The dome light that works with the doors seems to have no power to them.

We can probably make it right but first need to make sure we are on the same page and useing same terminoligy.
How did you arive at 2 volts and more important,we need to know exactly how many amps or mil-amps is being drawn.
Do you have a 12 dc amp meter and experience useing it?
The procedure is systematic so understanding one another is required else we will wind up chasing our tail.

I have a voltmeter connected between the ground cable and the battery ground post and it reads 2 volt.The positive cable is connected.I started pulling fuses one at a time untill the voltage went to zero.Battery reads 13.7 not running and 14 running.You can leave the cable hooked up all day as long as you keep useing it,but must remove it at night.

Look under the floor mat or carpet, also under the sill plates you may have some green rotted wires there.

Measuring the current draw might be a better way instead of measuring the voltage.
With the neg. batt. cable disconnected switch your meter to the amp setting and reposition the leads as required, most digital meters require that you move the positive lead from the volts/ohms setting to the amp setting. Then do what you have been doing, from the neg cable to the neg post of the battery. This will give you a better idea of how much current is being drawn.
So if you pull the lighting fuse the draw is gone but disconnecting the plug from the light switch does not make the draw go away. I'm sure there is probably more than one fuse for the lights so it is also important to know exactly which lights are run from the fuse you are pulling. That's where a service manual or wiring diagram come in real handy. Your owner's manual might also help in knowing what that fuse runs.

Do as inno suggested to find amps. If you have a helper available,have them watch the meter while you move/wiggle wires and/or disconnect wires.
When the meter drops,there's the trouble spot. Women and kid's hands tire quickly holding the meter probes tight so you could use a 12 volt bulb with aligator clips in place of meter. No helper? Scroung up a seat belt or other buzzer and hook it up the same way. The buzzer may sound weak and that's ok. It's simply running on 6 volts,the other 6 are being consumed by the short circuit. Push,pull,wiggle and unhook til the buzzer stops. Good luck and let us know how it gos so we can try something different.

"Its a 94 and i think there are no bulbs there.The dome light that works with the doors seems to have no power to them."

Might want to check the wires to the dome light switch to the doors, maybe a bare wire there or stuck/bad switch.

The dome light will work if the gauge light thing is turned up all the way,but there appears to be no juice at the door switches.I thought that a short there would draw 12 volts not 2.

Not if it's a high resistance short, something like a corroded wire or plug or a wire with a cracked insulating jacket that's wet and some current is "seeping" to ground.
I was going to suggest trailer or tail light wiring but there should be no current flow with the lights turned off.
The other thing you can do instead of putting the ammeter between the batt and the cable is pull the fuse in question and put the probes of the meter across the fuse contacts. That will tell you if that's your source of drain. Who knows, it could be more than one source. Many vehicles, especially the newer ones have some drain on them even when turned off.

Oh, and if you are measuring 2volts between the batt and the cable then whatever is causing the drain is soaking up 10 of the volts of your 12 volt battery and you are measuring the remaining 2.

often how the dome interior lights works is they have power constantly,but no ground.door swtches and things supply the ground circuit. they do this simply because it requires much less wiring. it also a lot of times throws folks off when they are trying to check the circuits because you cant simply check from one side of bulb to the other with a meter when light is supposed to be on. if you have a bad switch for instance, trouble shooting by checking accross bulb socket with a meter will show nothing.check from one side of bulb to ground,if you show 12 volts there,and light is not working and bulb is good you have a bad switch normaly.there is a condition however where this type of circuit can cause a battery drain. that is if the switch or wire to switch has a high resistance short to ground constantly. this particular problem might not cause bulb to light,But it will bleed off power... and just fyi.. normal type 12volt bulb does pull about two amps. pull the bulbs from lights to check for this. bulbs themselves can act as fuses in the right conditions. and they will handle up to several amps before they burn up..other places to check,alternator,brake lights. I do not know if you have one, but a floor mounted light dimmer switch can cause weird problems also. rust dirt and things that get inside can cause high resistance shorts. and thats possibly your culprit if it has one.that would also be in the light circuit,and should stop when light fuse is pulled. i dont recall a auto circuit where dome and headlights are on the same circuit, but it is possible. normally they are seperate.

Well it is the dome/dash circet that is bad i have that(small) reset fuse out and no drain.The problem now is the fan defroster allso don't work.So i have new toggle switch in place of the fuse with an inline fuse. Everything works with no drain with the switch off and i will have to remember to turn it on and off or find a source for juice from fuse panel from the main switch.

If you are using a digital multimeter to measure battery drain two volts is NOTHING. (I assume you put the multimeter in series with the battery.

Most DMMs have a 10 megohm input impedance. Two volts over 10 megohms is two-tenths of a microamp. That will fully discharge a 100 amp-hour battery in a little over fifty thousand years.

Nothing i use is digital.

(quoted from post at 03:38:16 12/06/12) If you are using a digital multimeter to measure battery drain two volts is NOTHING. (I assume you put the multimeter in series with the battery.

Most DMMs have a 10 megohm input impedance. Two volts over 10 megohms is two-tenths of a microamp. That will fully discharge a 100 amp-hour battery in a little over fifty thousand years.

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XACTLY! He never actually said that he even had a problem! Just dickin around measuring shi...I mean stuff.

(quoted from post at 14:10:26 12/05/12) Look under the floor mat or carpet, also under the sill plates you may have some green rotted wires there.

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I serviced "Schwans" trucks of that vintage. They had a recall program to inspect and repair the dome light circuit under the floor mat.

Remove the left sill plate. Lift the carpet from the park brake back to the seat. The recall involved inspection the the wiring harness making any necessary repairs and then install a loom to protect the harness and make sure it was correctly installed in the recess in the floor. Completed vehicles had a black circle sticker applied to the door to indicate the repairs had been made.

I don't know if the program applied to all TopKick trucks or just those owned by Schwans.

>Nothing i use is digital.

OK, thanks for sharing that information. So what is the input impedance of your analog voltmeter?

Analog voltmeters don't have an input impedance spec, instead they have a "sensitivity" spec, which is given in ohms per volt. Your meter should have this value printed somewhere on the panel. But let's assume you have a cheap POS meter with a 10K ohm/volt sensitivity and you're using the 20 volt range. That gives an input impedance of 10K x 20 = 200 kilohms. So if you're reading two volts, the current is 2 / 200K = 10 microamps.

Holy Toledo, you better do something about that! At ten microamps, your battery will be dead in 1142 years!

(quoted from post at 06:36:57 12/06/12) >Nothing i use is digital.

OK, thanks for sharing that information. So what is the input impedance of your analog voltmeter?

Analog voltmeters don't have an input impedance spec, instead they have a "sensitivity" spec, which is given in ohms per volt. Your meter should have this value printed somewhere on the panel. But let's assume you have a cheap POS meter with a 10K ohm/volt sensitivity and you're using the 20 volt range. That gives an input impedance of 10K x 20 = 200 kilohms. So if you're reading two volts, the current is 2 / 200K = 10 microamps.

Holy Toledo, you better do something about that! At ten microamps, your battery will be dead in 1142 years!

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tandard Delco alternator voltage sensing circuit draws 750 microamps all the time that battery is connected. The ECU & radio memory draw even more.

Read my previous post, if he was measuring 2 volts from batt post to cable that is the residual voltage, whatever is drawing current is taking up 10 of his 12 volts.

Neither you nor he understand basic electrical theory.