I have a 91 explorer sport that drains the battery in about 4 to 6 hours.
a multi meter between the neg terminal and the unhooked cable
reads 44.1 with the red lead in the 10A jack and the dial set at 200m
If i switch dial to 20m the reading is 4.1
What do those mumbers mean?

And just to check 1000m = 1 Amp?

 

That doesn't make any sense.

If we assume 200m is the 200ma scale, this means you can take an amp reading from zero to 200ma(which is .02 amps) and the meter will give you a reading.

So it looks like you got 44.1 ma or .044 amps.

If we assume the 20m is a 20ma scale, then 44.1 amps is too much for that scale, and you should get a "1" or something on the meter(an overload message). The number on the dial determines the max amount of amps that scale will read.

By the way 44.1ma is not much. I am suspicous this is not right if you have a serious battery drain.

 

Try this:

Take a test light, unhook the negative battery cable, hook one end of the test light to the battery ~ the other to the unattached cable, be sure the key is in the OFF position, if the test light lights up, well you have a drain, go into the fuse compartment, with the test light still attached, take out one fuse at a time until the light goes off, be sure to replace each fuse after you check the test light to see if it goes out. This will help you isolate the source. Good luck

 

Most meters that have a 10 amp plug are meant to be used with the range selected to 10 amps when the red lead is plugged into the 10 amp plug. The ma ranges should be used with the red lead plugged into the ma/volt plug. These are general observations that I have seen over the years using various meters.

 

franklin,
can't argue that it doesn't make sense. I am struggling to make sense of it. lol That's why I'm here.
After reading kioolt's post I figured out something I didn't know about the meter.
In the DCA range there are three positions for the range selector
200mA, 20mA, 2mA. with the 10A jack i thought that doubled the positions to 6.
Now i see that under the 20mA number on the meter dial is also
a line and 10A printed in red instead of green like the 200,20, 2 are.
That matches the four categories listed in the instructions (200mA, 20mA, 2mA and10A) and what kioolt says.

So with the red lead in the 10A jack, the range selector should be pointing to the 20mA/10A position. and to only that position if red lead is in 10A jack, right?

(havent' seen that bit off info in the instructions.) think i paid 7$ for it at the discount store. Figured if i fried it out of ignorance i wouldn't be out to much.

That would make my first set of mumbers meaningless then

Back to the number game, if 200mA is two hundredths then does it also follow that 20mA is two tenths and 2mA is two amps.
That doesn't make sense to me. does 2mA mean two milli amps?
or am i guessing wrong about what the "m" means.

Umm, doing that same meaningless first test of mine on a 96 ex down the street my mumbers are literally ten times as high as his.

 

jw,
I've done the testlight between the neg bat and the disconnected neg clamp. Thought i found the culprit in headlight circuit only to eventually discover the test light was bright because of the underhood light. It was wanting to draw power.
Pulled the underhood bulband test light only shows dim pulling all fusses one at a time won't make test light go out.

i've checked the underhood and glove box light. they do go out.
cig lighter is disconnected. radio is absent, looked for any bare wires there.

I have yet to disconnect the starter cables for a drain there.
I've read that the fender mounted solenoid can be a problem, but what's the difinitive test for it?

 

I'm interested in a post by Slade901

>>Probably the alternator is back feeding itself.

First, leave the battery positive and negative terminals connected. >Disconnect the positive terminal<and then connect a 12v test light between the battery positive terminal and the positive cable that you just disconnected.<<
**********************************
Does this mean that the bat cables stay clamped to the battery through out this test?
When he says "disconect the positive terminal" does he mean the positve terminal on the alt? or disconect it from the alt?

That's on an 88 F150. would that test work on my 91 Explorer?

 

On a digital multimeter you simply read the number on the display. If the meter is set on the 200 ma range and the meter reads 15 than you have 15 ma. If the meter is on the 20 ma range and the meter displays 15 you have 15 ma again. If you then put the meter on the 2ma range you would have an overrange, I'm assuming your meter would be flashing it's display or some other way to let you know of the overrange. Only on analog meters (needle type) do you do any multiplying of the reading.
To answer your question about the 10A plug. Yes, the range selector should always be in the 20ma/10A setting when the red lead is plugged into the 10A plug.

 

Time to throw in my .02 cents about your meters scale.

The meters you buy usually have the current scale like you describe. For most automotive stuff you will want to use the 10 Amp scale, which I think you have a pretty good grasps of - you have to move your test lead and turn the dial to 10 A.

The smaller scale is more suited for measuring the small current draw of say, a digital chip, or maybe the memory chip like the memory of your radio, ( which is possibly part of what your reading with the 44 mA.) A lot of people don't use the current reading part of the meter much. To read current you have to be in series and that isn't too bad between your battery and cable, but means unsoldering a component on a printed circuit board, (or pcb), when you're working on the smaller stuff. It's usually easier to measure voltage or resistence and calculate the current using Ohm's law, so you don't have to waste time with the soldering iron.

Whats that little m mean?

It just stands for milli. Kind of like using Meg for your processor or Gig for your hard drive, but used for units less than one.

200 mA = 0.2 Amps or 2 tenths
20 mA = 0.02 Amps or 2 hundredths
2 mA = 0.002 Amps or 2 thousandths, (very small).

In geek speak it's easy to say, "my gizmo is drawing 500 mills." From that I know it's half an Amp. That doesn't seem too bad. I have a pretty good grasp of what an, "Amp," is.

Now, the next scale down from milli is micro, (instead of the little m, it uses the little u - as in uA. 1000uA=1mA). It's easier to say somethings drawing 50 microamps than it is to say, "it's drawing 0.00005 Amps." I get lost in the zeros. (Believe it or not, with a little practice, you can convert in your head.)

Either you understand a little better now, or I've really confused you! Try hooking your meter up between the battery and cable again with the underhood bulb disconnected and see what you get, Amp wise. Start at the 10 Amp scale and work your way down till you get a reading. If your reading in the Amps, leave the meter set up at the battery like you have it and disconnect the wires off the alternator. Then see if the current draw drops way down. Basically, your just trying to isolate the problem. That's where the fuse pulling, one at a time, comes in - just trying to isolate. Remember, anything that uses memory draws a little current, like in the micros to the small millies...

 

I don't know of a definitive way to test the solenoid, if I find something I will let you know.

I say disconnect the alternator as mentioned above, see what happens. Maybe its a bad battery? Good luck

 

thanks guys the info was helpfull
Here's the update afte more poking,prodding and studying the manual.

the drain is now showing to come thru the engine side 15A fuse in the power distribution box. Book wouldn't tell what it was but the inside of the cover does. It runs the Alt field.

It's the hot at all times Y/w wire, goes to the voltage reg.
But I can't figure out how to isolate the alt from the reg.
I don't know what's supposed to be hot and what's not.
I don't know enough to figure that out from the schematic.

The thick B/O wire bolts to the back of ALt. So what's suppossed to be hot with key off? Namely that W/B wire single plug in.
Anyone know?

On the three prong plug,The LG/R to the reg is hot when in run or start. The Y/W is hot at all times from the 15A fuse (alt field)
And that W/B wire loops from reg to alt.

If i pull the W/B wire off the alt, the test light goes out. But which side is the drain coming from?

 

What are your replacement options? Does a new alt come with a new regulator? If so, just replace the whole mess.

 

the link veiwer to autozone(?) list's alt's from about $99 to $190.
A Reg is $43.00

I pulled the alt off and seperated the two thinking that grounding them seperately one would light up the test light and that would tell me which one was bad.
Neither one would light it up.

the Reg comes off with the brush holder and one brush is hot. It is not the one that has the words "ground here to test" pointing to it

 

After joining this site I found myself wishing guys would come back and tell what they found as the problem. Now i know why they don't. It's, "I'll do it later or tomprrow". So I'm guilty too.
Anyway to finish the saga. My solution was a used one from a salvage yard.
Found one for $25, no core. Brought it home and did a little mix and match with the reg and brushes. Mine had brushes long enough that the pin holes were still showing, so i put the 'new' used regulator on mine.
Now it carries slightly higher volts but the big difference is there is no drop with an elec demand.

This part is for any more newbies to volt meters. I've always driven older trucks with amp meters. when you put a demand on the elec system the gauge moves to the left. Unless it goes into the neg, no prob right?
Ok so one night i turned on the headlights & blower, the volt meter in the 91 expy moves from its position on the right to about center and i don't think anything of it because i don't know any better. Well, i do now!
That would have been a clue to test the voltage running under a demand/load. With the new reg the gauge stays to the right.

I still wonder why I couldn't seperate the reg from the alt and (with each grounded) have one show up as being the culprit since they each have an 'always hot'.