Battery drain, tested no drop pulling fuses?

blksn955.o · May 3, 2011

I have been fighting a battery drain issue for some time now. I built a stand alone fuse panel for any aftermarket items (line lock, gauges, n2o, bottle warmer, and gauge lights) to isolate those. I went and tested with a meter and after pulling every fuse under the dash moved to the under hood fuses with no drop anywhere. I then started pulling main power lines. I pulled the stereo main power (aftermarket system) no drop, I pulled the stand alone fuse panel main power and nothing, and I also pulled the alt power source with no change I also pulled the other 2 alt wires just to make sure.

The only thing I can think of is maybe I am setting up my meter incorrectly? The reason I think this is the only way I can get a reading with the (-) neg terminal undone it is (- 5.87) and that does not seem correct.

I have the black lead on the COM slot and the red lead plugged into the Ohm slot. The dial is on the black 20M on the Ohm side (3rd click/spot clockwise from off)

blksn955.o · May 3, 2011

I am going to try and undo the negative terminal and let the meter sit for 30min and try again as I just read that the reset could artificially be spiking the numbers for up to 30min.

HISSIN50 · May 4, 2011

You need to measure current draw (in amps), not Voltage.

blksn955.o · May 4, 2011

So just so I dont not setup the meter incorrectly what settings and setup should I use with the above meter pic?

I am thinking it would be the red wire plugged into A and the black wire plugged into COM. The dial turned to A on the 20m (the one approx at 7 o'clock)?

HISSIN50 · May 4, 2011

Your approach sounds good to me.

You'll need your meter in-series with the disconnected negative battery cable and battery post. Just be sure you do not do anything to create a load because it can blow the meter's internal fuse.

blksn955.o · May 4, 2011

That is what I was doing, using the undone neg cable.

Thanks for the help and correcting my approach.

blksn955.o · May 4, 2011

With the settings on the meter as I described I get a 0.00 reading.

This is a new meter the only time prior I have used it is to test with a 9v battery.

blksn955.o · May 4, 2011

Fuse is blown in the meter, will need to run to the parts store and pick up a new fuse if I can find one.

blksn955.o · May 4, 2011

fuse looks to have popped at first touch. I blew 1 of the replacement fuses I picked up instantly. I had to take the neg terminal off while having the lead attached to the batt. so there was no spark.

Its the #8 fuse, for the radio (think this is the culprit), interior light, glove box light, trunk light ext. Pulled the interior lights...will check the cluster and trunk lights while I go over every inch of the stereo wiring.

HISSIN50 · May 5, 2011

You have the doors closed and underhood light off during the testing, correct? Everything must be off.

A shunt is an option but it might be out of the question. A test light can be used in lieu of a meter. Just be sure you don't have some massive draw that will melt the test light's wire. If you can get the test light's illumination down to less than a full glow, you should be able to use the meter again.

S351Saleen77 · May 5, 2011

HISSIN50 said:
You have the doors closed and underhood light off during the testing, correct? Everything must be off.

A shunt is an option but it might be out of the question. A test light can be used in lieu of a meter. Just be sure you don't have some massive draw that will melt the test light's wire. If you can get the test light's illumination down to less than a full glow, you should be able to use the meter again.

Good advice getting the test light to go dim before hooking up your meter! I don't want to take chances melting my Fluke so I use a $4 meter from Harbor freight to make sure I'm not going to melt anything before I hook up my Fluke. I melted the tips off my probes once!

Also I just did this on a Foxbody and I was pulling wires off the starter solenoid (hot side) one at a time until I found which one was causing the drain.

blksn955.o · May 5, 2011

HISSIN50 said:
You have the doors closed and underhood light off during the testing, correct? Everything must be off.

A shunt is an option but it might be out of the question. A test light can be used in lieu of a meter. Just be sure you don't have some massive draw that will melt the test light's wire. If you can get the test light's illumination down to less than a full glow, you should be able to use the meter again.

I pulled the interior light, and the underhood light has been gone for years, door chime does not work if the keys are out. I was able to use the meter as posted above it was the #8 fuse. I pulled the head unit of the stereo and no drop in voltage, I pulled the main power line to the amps and there was a drop but from 1.87 to 1.27 (will be going over my main power line and grounds, but obviously not the whole issue if its still 1.27). I am going to pull my digital EQ as I have not pulled it to see. I also want to pull the cluster and check for any shorts or anything.

The meter is fine, thankfully. I just had to keep the lead on the post of the battery as I pulled the cable off.

blksn955.o · May 7, 2011

Now I am puzzled, none of the cluster items are the drain, the stereo is fine outside of the amp wires (not the main culprit, as they are pulling .6 and something is pulling more than that) as after undoing the amp wires it is still 1.27-2.51 when I tested last night...somehow the draw went up from the night before? I gave the system 30min to reset as it started out at 4.x.

I think it may be a short between the fuse box #8 fuse and the items it powers as none of the items when unplugged cause a drop in draw. Has anyone taken out the under dash fuse panel?

will_95gt · May 7, 2011

Out of curiosity, what fuse box diagram are you looking at? I'm currently running through the same gamut of tests that you are and have also narrowed my culprit fuse down to #8. The diagram I'm looking at, however, offers a different list of protected circuits for that fuse:

http://mustangstock.com/wp-content/uploads/MustangFuseBox.gif

What gives?

Edit: Hmm, I found another one that lists devices in accordance with your post. Is the first one I posted to a fox body or something? I just noticed the fuse ratings are also different.

HISSIN50 · May 8, 2011

That first link is definitely a fox fusebox.

will_95gt · May 8, 2011

lol, thanks for clearing that up. Glad I didn't spend an afternoon checking all the wrong stuff. For the record, I found my current draw! There was a short in my radio wiring harness. All I have to do now is charge the battery and I'm back in business.

BLKSN, any progress with yours? Did you decide to investigate the fuse panel itself?

blksn955.o · May 8, 2011

I need to check the harness/lines to the items for shorts. I as a first round unplugged the units to check the components themselves and inspected the wires I could see/access with the head unit/equalizer out. I want to pull the fuse box to see if anything is visible at the box end before I go fishing for wires and testing power sources for shorts.

The reason I am hesitant/testing the power sources for shorts is the issue of a single car garage (small, cant fully open either door) and weather. It has been a tad wet (flood due to this) and getting under the dash in a small garage is a pain.

will_95gt · May 9, 2011

At least you have a garage...I get mean looks every time I start tearing my car apart in my apartment parking lot, lol. Good luck with the short-hunt, keep us posted.

bayellowstang · May 10, 2011

I set out to find mine this weekend. It didn't take long at all. My parking lights and high-speed fan switch were on. Along with the a/c /fan on high turn signals and windshield wipers. I must have forgotten to lock it and my 3 year old got in and was playing in it. By the time I got home it must have been dead, I never heard the fan running or saw the lights on.

She said she was sorry for breaking the racecar, I had to laugh. I gave the wife hell for not noticing she was in it though.

I still need to check it though. What voltage is considered acceptable?

blksn955.o · May 10, 2011

I saw .5 ish on the draw as far as a target goes. When I pull the amp wiring and fuse 8 it drops to between .07 and .12.

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