draw

[Tim]

my battery keeps going dead and i dont have anything turned on. usually takes a week or two for it to get real low while sitting.

how do i check for a draw with a cheap-o multi meter? please be specific because i am multi meter impared

[TObject]

Disconnect one of the battery cables, and put the meter in the Amp-meter mode (DC Current). Start with the largest setting, Amps, then go down to hundreds of milliamps, tens of milliamps, milliamps, and so on, until you get a reliable reading.

If you disconnect the negative cable at the battery, the black cable of the multimeter should go to the battery post, and the red cable should go to the disconnected battery clamp.

Multimeters usually have a separate "hole" for the red cable for when you are measuring Amps, rather than Volts or Ohms.

[Jerry Bransford]

Also make sure that if where you live in Washington could cause a salt build-up, like if you lived near salt water, that you throughly rinse/scrub the battery and its connectors off. If present, a salt build-up causes a leakage path for between the battery and ground.

[DanB98TJ]

You can also pinpoint the circuit causing the draw using just a test light. Disconnect the positive terminal, connect the test light between the terminal and battery, and pull fuses until the light goes out. Then you can start tracking down everything on that circuit for shorts, etc.

Regardless of what some people tell you, it is possible for the stereo memory circuit to draw enough juice to light the test light. I actually tried using Sergey's process with a multi-meter but never got a reading. Maybe my meter didn't go low enough to pick up that small of a draw?

I went through the whole process of trying to track down a constant draw a year or so back, and it turned out that the battery was just starting to fail. Everything was fine if I drove the truck every few days, but if I let it sit any longer it would have to be jumped. After a few weeks of that the battery finally took a terminal dump in a short period of time.

[Tim]

Originally posted by DanB98TJ
You can also pinpoint the circuit causing the draw using just a test light. Disconnect the positive terminal, connect the test light between the terminal and battery, and pull fuses until the light goes out. Then you can start tracking down everything on that circuit for shorts, etc.

Regardless of what some people tell you, it is possible for the stereo memory circuit to draw enough juice to light the test light. I actually tried using Sergey's process with a multi-meter but never got a reading. Maybe my meter didn't go low enough to pick up that small of a draw?

I went through the whole process of trying to track down a constant draw a year or so back, and it turned out that the battery was just starting to fail. Everything was fine if I drove the truck every few days, but if I let it sit any longer it would have to be jumped. After a few weeks of that the battery finally took a terminal dump in a short period of time.

i hope its not the bat.. its not even 2yo yet. pc1700 odessey (not sure i ever spelled that right...lol)
thanks guys! i will look at this stuff when its charged back up.

[Tim]

finally got around to looking for the draw. it is coming from fuse 17 (red 10 amp) in the block next to the battery. near as i can tell it is a 11.5ish volt draw and pulsating when using a test lamp. it is strong enough to run a small bulb but not a tail light bulb there is one lamp out in the dash but i dont think that has anything to do with it.

any ideas?

[Stu Olson]

You do have an alarm system?

The draw is measured in current, not volts. When you put the multimeter in current mode, note the scale you are using. Probably 0-2, 0-20, 0-200, etc. Note if the scale you are using is milliamps (MA) or amps (A).

[Jerry Bransford]

Originally posted by T.Dome
finally got around to looking for the draw. it is coming from fuse 17 (red 10 amp) in the block next to the battery. near as i can tell it is a 11.5ish volt draw and pulsating when using a test lamp. it is strong enough to run a small bulb but not a tail light bulb there is one lamp out in the dash but i dont think that has anything to do with it.

any ideas?

Any chance you have installed an old-fashioned mechanical clock like an aircraft clock on your Jeep? The pulsating current makes me think of that.

[Tim]

no alarm or clock.
have the ADE though....
stu, i think it was in the 0-20 mode. im a total retard when it comes to multimeters...

[Scott_KY_98TJ]

Pull that fuse and the the only thing that shouldn't work is the rear defogger. Guess your wired up for a hardtop? If you haven't installed anything else into this circuit, I'd wonder if the relay in the PDC is stuck. Your ADE shouldn't effect this circuit at all.

[Tim]

Originally posted by Scott_KY_98TJ
Pull that fuse and the the only thing that shouldn't work is the rear defogger. Guess your wired up for a hardtop? If you haven't installed anything else into this circuit, I'd wonder if the relay in the PDC is stuck. Your ADE shouldn't effect this circuit at all.

i pulled the relays one by one with the test lamp on and connected. the only thing that turned the light off was the 17 fuse in the underhood box. i have no hard top wiring either.
dad came by while i was doing this and he yanked the fuse for me when i had the key on. it turned the odometer off.

97 tj

[JLemieux]

Without looking at the wiring diagram, I would say the fuse you are looking at (#17) is the fuse labeled IOD. This stands for Ignition Off Draw. This is the circuit that keeps the computer memory powered up. If you were to remove this fuse to stop your battery from going dead, the PCM would have to go through a re-learn procedure every time you plug it back in. Just like if you were to leave your battery disconnected for an extended period of time. There should be less than 2 milliamps (.002 amps) being drawn through this circuit, not enough to draw down the battery you have in a month.
Don't remove this fuse to solve your problem unless you are not starting your jeep for extended periods of time. That is it's purpose. This fuse is removed when the vehicle is new and is being shipped around the country so the battery doesn't go dead in shipping.
If you are sure there is no other draw than your battery has a problem.

[Tim]

you are correct it is the iod fuse. when i pull it the draw stops. i think it is pulling more than it is supposed to. should that draw be enough to light up a bulb?

when i have a little time i will post a pic of my multi-meter and you guys can tell me where to put the dial and which port to put the red wire.

i have been disconnecting the battery when the jeep sits for a week or two and it seems fine when i reconnect to use the jeep.

[JLemieux]

Originally posted by T.Dome
should that draw be enough to light up a bulb?

It depends what the wattage is on the bulb.