Huge Parasitic Battery Drain Problem
- Thread starter pax
- Start date
TheDurk
Elite Member
I last had a car fail emissions around 2003 (not the 4Runner, which has never failed), so I may be out-of-date and they keep changing rules. I know there is a limit, but you get at least two re-tests. It may be just the time limit. Sorry.
I hate going to inspection. I always use the appointment system (Washington, in my case.) Much better than the lines.
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I think that I found the problem. Combination of two things made this problem much worst than it should have been.
The primary problem was caused by using some of that real cheap vinyl tape that I used years ago that the adhesive broke down on the clock harness system. I may have even fixed that back on Tuesday or so when the amps dropped.
The other secondary problem was the replacement multimeter I got this past weekend was defective from the start. Found my old one yesterday afternoon and right off the bat my readings were good (the <blank> defective stills shows a draw of 7.5 amps). So I have been wasting days of my time hunting down ghosts that may not have been there. I did used a standard to verify the old one was right.
Tested the system this morning and my world is good. Hopefully this problem is gone.
Notrayray...lol...looking at the service bullet. The ECU has to sit powered on for at least 8 hours before Evap system will even ready itself to record. I was doomed before I even started to DMV yesterday. That was a great help in understanding and reassuring. Thanks for that.
Time to go find a quiet trout stream so I can marvel at my lack of ability at fly casting....
Thanks for all your input guys.
The primary problem was caused by using some of that real cheap vinyl tape that I used years ago that the adhesive broke down on the clock harness system. I may have even fixed that back on Tuesday or so when the amps dropped.
The other secondary problem was the replacement multimeter I got this past weekend was defective from the start. Found my old one yesterday afternoon and right off the bat my readings were good (the <blank> defective stills shows a draw of 7.5 amps). So I have been wasting days of my time hunting down ghosts that may not have been there. I did used a standard to verify the old one was right.
Tested the system this morning and my world is good. Hopefully this problem is gone.
Notrayray...lol...looking at the service bullet. The ECU has to sit powered on for at least 8 hours before Evap system will even ready itself to record. I was doomed before I even started to DMV yesterday. That was a great help in understanding and reassuring. Thanks for that.
Time to go find a quiet trout stream so I can marvel at my lack of ability at fly casting....
Thanks for all your input guys.
electronbob
New member
similar problem
hi all,
I have a 2004 4runner, 4x4 sport, and the ecu-b fuse blows every time it rains. A few warning lights go on related to stability control, the A/C settings re-set each time the car is turned off, and I lose the ability to unlock the vehicle with the key-fob. I am still able to arm the alarm, though. Then, after a variable time (weeks - months), I can replace the fuse without it blowing and regain normal function (key-fob access/door locks, etc).
The first time this happened, I almost lost several hundred dollars to the dealer for "diagnostics" before it spontaneously resolved during their analysis - the only change I could divine was that they had taken the lid off the left-of-steering-column fuse box in the cab, and thought maybe something down there had the chance to air out enough to eliminate a water-induced short.
It just happened again today with the rain, and googling brought up this recent thread.
Anyone out there know where I should be looking for this short, maybe some common area for water to collect that could short a bare wire or terminal to ground that folks out there know of? I don't have any perceivable leaks in the cab.
hi all,
I have a 2004 4runner, 4x4 sport, and the ecu-b fuse blows every time it rains. A few warning lights go on related to stability control, the A/C settings re-set each time the car is turned off, and I lose the ability to unlock the vehicle with the key-fob. I am still able to arm the alarm, though. Then, after a variable time (weeks - months), I can replace the fuse without it blowing and regain normal function (key-fob access/door locks, etc).
The first time this happened, I almost lost several hundred dollars to the dealer for "diagnostics" before it spontaneously resolved during their analysis - the only change I could divine was that they had taken the lid off the left-of-steering-column fuse box in the cab, and thought maybe something down there had the chance to air out enough to eliminate a water-induced short.
It just happened again today with the rain, and googling brought up this recent thread.
Anyone out there know where I should be looking for this short, maybe some common area for water to collect that could short a bare wire or terminal to ground that folks out there know of? I don't have any perceivable leaks in the cab.
notrayray
New member
The FSM says the ecu-b fuses powers the a/c and the headlights/daytime running lights.
Wiring diagrams here..
http://www.ncttora.com/fsm/2003/Wiring_Manual/03tacoma/systemci/054ac.pdf
and
http://www.ncttora.com/fsm/2003/Wiring_Manual/03tacoma/systemci/022hldrl.pdf
Any mods to the drl's?
I would probably start looking in the headlight area, since it's exposed to the elements more than the a/c system.....
Wiring diagrams here..
http://www.ncttora.com/fsm/2003/Wiring_Manual/03tacoma/systemci/054ac.pdf
and
http://www.ncttora.com/fsm/2003/Wiring_Manual/03tacoma/systemci/022hldrl.pdf
Any mods to the drl's?
I would probably start looking in the headlight area, since it's exposed to the elements more than the a/c system.....
Hey E-Bob,
You had your windshield replaced before the problems started or it got cracked? It's rains and you get an electrical short, you got leak some where along the edge of the windshield. That is the first place I look at. Fix the leak, and the problems should go away.
You can get a independent glass man to put in a new sheet or redo the seals on that one far less than you spent on that dealer diag. Plus they give you a warranty against leaks. Of course there are also the glass chains that will charge you more but are good if you plan on moving soon.
Hope that helps. Let me know how that turns out for you.
You had your windshield replaced before the problems started or it got cracked? It's rains and you get an electrical short, you got leak some where along the edge of the windshield. That is the first place I look at. Fix the leak, and the problems should go away.
You can get a independent glass man to put in a new sheet or redo the seals on that one far less than you spent on that dealer diag. Plus they give you a warranty against leaks. Of course there are also the glass chains that will charge you more but are good if you plan on moving soon.
Hope that helps. Let me know how that turns out for you.
electronbob
New member
thanks for the quick reply. No mods to the lights. They do still light up when I arm/dis-arm the alarm.
electronbob
New member
I have a hairline that I had repaired at the top of the windshield, but that was after the first episode of this rain-induced ecu-b short. I haven't noticed any leaking around the seal. (I was lucky with the dealer diag, since it spontaneously resolved during their analysis, and they had no idea was was going on, they were forthright about it and did not charge me.)
All of the goodies for the ecu-b is pretty much right under the windshield on the driver side that you describe. It takes only a drop of water to short the system out. My money is still on the windshield leaking, it's the most common denominator here and the simplest answer which is normally the right one.
electronbob
New member
that does make sense, I will look into re-sealing the windshield. In the meantime, is there an easy way to look / known location where water might be pooling in that area, so I can dry it out? Even if I re-do the seal, I would still like to dry out collected water re: corrosion / mildew. (Also, if I knew there was a region prone to a short to ground, I would insulate it myself, simply knowing a short can occur in this manner concerns me.)
I realize that if all of this is behind the dash, I have no quick way to access it (and minimal experience / desire to take out the dashboard).
I realize that if all of this is behind the dash, I have no quick way to access it (and minimal experience / desire to take out the dashboard).
Which "cable" are you referring to? I'm experiencing the same issue as the original poster on this thread.
It's a 7 year old thread and the guy hasn't posted for 6 years.
In any case, he means the negative cable.
Parasitic draw... only removing the white cable to bottom of fuse box helps...
I am about to go beserk. 97 4runner dies every night without unplugging the white cable that comes from the positive terminal and goes into the bottom part of the fusebox. i have attached a multimeter between the negative post and negative cable and it shows 12.5 amps... unless i remove that white cable which drops it to .01. i have removed the cables to the alternator and it stays at 12.5. i have removed every fuse and it stays at 12.5. I can't get to the starter to drop power there but i pulled the ignition relay fuse with no change. any ideas?
I am about to go beserk. 97 4runner dies every night without unplugging the white cable that comes from the positive terminal and goes into the bottom part of the fusebox. i have attached a multimeter between the negative post and negative cable and it shows 12.5 amps... unless i remove that white cable which drops it to .01. i have removed the cables to the alternator and it stays at 12.5. i have removed every fuse and it stays at 12.5. I can't get to the starter to drop power there but i pulled the ignition relay fuse with no change. any ideas?
s20004runner
New member
my parasite was a rear hatch light. I always leave it off unless I need it. hope you fix it soon, it sucks for sure.
I also carry a portable battery jump start pack - this one came in a nice case w/ all the wires. https://www.amazon.com/gp/product/B01D42TYFC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Parasitic draw... only removing the white cable to bottom of fuse box helps...
New battery.... drains with the negative battery terminal removed. Only thing that keeps it from draining is the removal of the positive cable or just the positive cable that goes to the bottom of the fuse box. i'm close to setting it all on fire.
New battery.... drains with the negative battery terminal removed. Only thing that keeps it from draining is the removal of the positive cable or just the positive cable that goes to the bottom of the fuse box. i'm close to setting it all on fire.
Somnospeed
New member
REviving the dead.... I'm experiencing the same slow drain issue. If I go three days without driving my gen 4 4Runner, the battery will be completely dead, as in not even a click when the key turns or dome light flickering. I just put a brand new battery in a two weeks ago.
I checked a few fuses but haven't gotten to all of them, though judging by the responses I've seen in this thread and similar ones, fuses are not likely the issue. I plan to have the alternator tested, but not one person in this thread had a bad alternator.
I had a remote starter installed back in December, but not one time during the winter did I experience a dead battery. I have a 2nd car that I drive when it's nice out so the 4Runner can go 4-5 days without being driven, but this latest battery drain happened on less than 3 days.
I'm hoping someone has something to add or something I can check myself. I'm FAR from being crafty under a hood though, so unfortunately, I'm not skilled enough to dig deep into electrical systems. :dammit:
I checked a few fuses but haven't gotten to all of them, though judging by the responses I've seen in this thread and similar ones, fuses are not likely the issue. I plan to have the alternator tested, but not one person in this thread had a bad alternator.
I had a remote starter installed back in December, but not one time during the winter did I experience a dead battery. I have a 2nd car that I drive when it's nice out so the 4Runner can go 4-5 days without being driven, but this latest battery drain happened on less than 3 days.
I'm hoping someone has something to add or something I can check myself. I'm FAR from being crafty under a hood though, so unfortunately, I'm not skilled enough to dig deep into electrical systems. :dammit:
plcfcng
Member
So I hope I can help you narrow it down. First clean your battery post and while your at it check the water level and use distilled water if they need to be topped it off and wash the top of your battery off with a little soapy water as dirt can cause a parasitic leak. Next you can go to a Autozone or Orelley and they can check your battery and charging system. Also look at the condition of your cables.
If you can get a battery charger it would be great if you can charge up the battery and it still goes dead after a few days here is the way to look for a Parasitic leak using simple tools.
So if your looking for a parasitic leak unplug your neg terminal of the Batt and clip a test light between the post and the cable so the way it looks is a disconnected cable with the test light in the middle.
With the key out of the ignition with everything off you should not see any light or only a very dim light coming from the bulb.
Now open your car door so your dome light is on and look at the bulb again the bulb should be bright.
When you close the door and the dome light gets dim again thats what you want.
If the light is bright turn off the dome light when the door is open and go to the fuse box and remove each fuse one at time until the bulb dims.
So the way this works is if there is enough current/amperage to light up the bulb that's too much so the hunt starts if the light is dim you need to look else where. if you don't have a test light you can make a tester with just a bulb, holder and some wire and a way to clamp them to the post and cable. This allows you to isolate the circuit instead off running in circles trying to find whats wrong. Look for aftermarket items/add on's first or recent changes. What you may find is your battery maybe going bad and it just time to change it but A zone or Orelly will be able to determine that.
I know that's alot but this should cover all the bases..:usa2:
If you can get a battery charger it would be great if you can charge up the battery and it still goes dead after a few days here is the way to look for a Parasitic leak using simple tools.
So if your looking for a parasitic leak unplug your neg terminal of the Batt and clip a test light between the post and the cable so the way it looks is a disconnected cable with the test light in the middle.
With the key out of the ignition with everything off you should not see any light or only a very dim light coming from the bulb.
Now open your car door so your dome light is on and look at the bulb again the bulb should be bright.
When you close the door and the dome light gets dim again thats what you want.
If the light is bright turn off the dome light when the door is open and go to the fuse box and remove each fuse one at time until the bulb dims.
So the way this works is if there is enough current/amperage to light up the bulb that's too much so the hunt starts if the light is dim you need to look else where. if you don't have a test light you can make a tester with just a bulb, holder and some wire and a way to clamp them to the post and cable. This allows you to isolate the circuit instead off running in circles trying to find whats wrong. Look for aftermarket items/add on's first or recent changes. What you may find is your battery maybe going bad and it just time to change it but A zone or Orelly will be able to determine that.
I know that's alot but this should cover all the bases..:usa2:
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