Parasitic battery drain

Anybody know why the wiper circuit would have a draw when the truck is off? Recently my battery crapped out on me, or so I thought. It was pretty old so I bought another one. I got a group 31 northstar which is stronger than the previous 24f. About a week later I got in my truck and it wouldnt turn over. Checked charging system and its good. Checked all the bullshit Ive added and nothing pulls a draw when off. So I started going thru the fuses one by one. On the 30A wip circuit it showed a draw. Removed the test leads and checked again. On the second try it read 0. I dont know what the hell is going on. I read a bunch of threads about wipers turning on by themselves but I havent had any issues with mine. Anybody got any ideas?

 

The only way the wiper circuit even has power is through the ignition switch. The current flow chart shows this as the path for current on the Wiper Circuit.

Battery >> Alt Fuse 120/140 Amp >> 50 Amp AM1 Fuse >> Ign Switch AM1 >> 30 Amp WIP Fuse >> Wiper Switch >> Wiper Motor >> Ground.

So if the ignition switch is off the wiper circuit has no power or current unless the ignition switch is defective ( which I doubt ).

Your reading you got on the WIP Circuit was probably not a valid reading for whatever reason... Do it again.

 

Yep, I did it twice and the second time it read 0. Load tested the battery at 200 amps and it checked out. Have a digital volt meter in the dash and it reads 13.6(roughly) with engine running so I am assuming charging system is up to par. Everyrhing reads 0 with truck in "sleep", so Im at a loss.

 

I'm at a loss as the power should be at a open circuit at the ignition switch.

 

try pulling

 

Its not pulling a draw. I checked again today and it reads 0. Everything is reading 0. Either my multimeter is toast or Im doing something wrong. I have added a bunch of shit, two amps, headunit, lighbar, pods, cb, water tank and pump, oac, ect. But I pulled the fuses on all of them one at a time... still drained. Then I pulled all of them at the same time thinking maybe its a multiple draw problem. Same result. The whole reason I opted for a bigger battery was to avoid draining it so fast. I will go through and check my relays tonight but so far I cant figure out what the hell is going on. Thabks for your guys input though, much appreciated.

 

This is your friend.

 

Dont forget a fault in alternator can cause problems..It could be a diode or regulator fault causing a slight drain; also can be hard to diagnose with different performance when cold or hot ....13.6 v may be ok, but if battery is partly drained, it probably should show in the 14's volts when just started. Maybe pay to have the charging system checked overall seeing as you've invested in a new battery.

 

Good idea on the alternator, will check. However my cheap mm was screwed up afterall. I borrowed a friends high end one and did find a problem but not sure what to make of it. The white ST fuse thats called short pin is drawing current as well as the 7.5 ecu-b right next to it. They both dropped the mm from 0.890A down to 0.025. Anybody know what direction I should look in? Any help is appreciated and thank you to you guys that have posted ideas so far.

 

I was lookin at that too haha. But I am skeptical, seems to good of a price to actually work.

 

Ok i can help make this a little less painful I have diagnosed a fuck ton of stupid draws. Simple tests first. After hours of sitting, touch things with ur hand, touch fuses, relays, alternator, deck. If any of them are warm at all, its on and most likely the cause.

Are you using an actual multimeter? If yes, Are the fuses good in the meter? They are 5 and 10amp fuses and everyone blows them. How are you using it to test amp draw? From what im reading you are unplugging fuses and testing between those circuits? If so thats not right.

Posting this from another post ive made.

To test for parasitic draw correctly, you have to set the meter to amps, just go to 10amp setting. take the negative post off the battery, connect each end of the meter to the neg post and neg cable. NOT neg to positive.
(you are supposed to do this without ever breaking connection to the battery but that usually doesn't matter unless its a computer making the draw as disconnecting the battery would reset them all and hide the problem)

Now a reading of 0.05(different for all vehicles/options but 0.05 is a good avg) or lower is good. Alot of the time I only find draws of 0.5amps but that will kill a battery.(usually I find the draw to be between 1-5 amps)
If you have a draw that is higher then normal, you pull 1 fuse at a time watching the reading. Leave the fuse you pulled out - Explained below.(take a pic of the panel) Once it drops you know the circuit.(usually aftermarket stereos, alternators, or a light in the cab).

Lets make it a bit more complicated. All these newer fandangled vehicles with computers on computers make this a bit more difficult. Firstly, when your meter re makes the circuit to the battery, every comp is going to reboot and show a draw, this can take up to 30 mins before they all go back to sleep.(some gms take up to an hr). Its painful but just leave the meter on and connected and come back to it in a bit. Also pulling a fuse and reinserting it can cause the comp to reboot as well, which is why you leave the fuse out as you work your way through.

Hopefully I explained this well enough, I can do it with my eyes closed but explaining shit is hard lol.


As for that tester posted above, just use a multi-meter. won't let you done.

 

Hmmm I like this idea alot. I wonder how warm the individual troubled circuit fuse would get (obviously dependent on ambient temp and probably amperage) compared to the others without a draw.

There are VERY accurate infrared thermometers available for ~15$ on Amazon that would nail it down pretty quickly checking round the fuse box assuming they do get a little warmer.

 

No I got everything you are saying. I did connect the meter exactly as you described. The only part you said that I didnt do was leave the fuses out as to not cause a reboot. I wasnt aware of that. As for connection time I set it up and walked away for almost two hours before beginning the test. The meter is a fluke multi meter but dont remember the model off hand. Had set on amps, 10 I believe. Nothing went below .8 until I pulled the ST and the ecub fuses. Then it was .25 but havent checked alternator yet. One of my amps does pull a draw but I have a circuit breaker in line that I manually turn off when I park. Even then I checked to see and it only went from .8 down to .75

 

The Short Pin is not a fuse just so you know what it is. It is just a connecting conductor to the following circuits.



It is removed during shipping so that these circuits will not drain the battery during storage and shipping as they are always drawing power even with the ignition switch off. When the truck arrives at the dealer the Short Pin is installed and those circuits are then energized.

And you should note that the ECU-B is fed from the Short Pin. So it appears that the ECU-B is drawing the current or something the ECU-B supplies is drawing it.

Here is an overall system drawing :

http://www.customtacos.com/tech.old...06toyewd/06toypdf/ewd/2006/tacoma/m/em01d.pdf

 

Which goes hand in hand with me saying usually stereo. Seen countless aftermarket decks causing the draw, sometimes poor wiring, usually faulty deck.

 

OK.

 

Thanks guys thats the help I needed. Now I have a direction to go in. I installed the hu, amps, ect. So I will start from the beginning and work my way through the whole setup just to be sure my wiring is solid. If it is the hu I hope pioneer will be willing to work with me. Ive installed audio systems in vehicles since highschool and never had any issues but everybody screws up once in a while. Much appreciated fellas.

 

Good luck in your quest!

 

Awesome thread, and learned a lot about testing for parasitic draws. Will be following along for the cause.

 

short or fuse popped?