Dead Battery (3x in 2mths) - 30A BAT Fuse has 500mA draw - what next? (2 Viewers)

[Julian Stead]

Just a quick explanation into how we used to find battery drains in the dealership, if the drain is intermittent then it is obviously harder to find. We used to use an amp clamp, this goes around the battery lead without any disconnections, then you would lock the vehicle but keep the bonnet open, you will have to hold bonnet switch down if one is fitted. Wait a few minutes after locking to ensure shutdown. Then read the amp clamp, you are looking for 100 mA (0.1A) Max, if any more then start pulling fuses untill drain disappears. Figure out what that fuse does then disconnect components to try and isolate fault. If the drain doesnt go after disconnecting fuses then you will need to disconnect the alternator, then the starter motor as these can cause a drain.

Most common cause is interior lights, radio including accessories, sat nav, water ingress, alternator. Anything that has a permanent supply is suspect but these are the most common. Disconnect any extras like tow bar electrics.

 

[GregLCA]

Just a quick explanation into how we used to find battery drains in the dealership, if the drain is intermittent then it is obviously harder to find. We used to use an amp clamp, this goes around the battery lead without any disconnections, then you would lock the vehicle but keep the bonnet open, you will have to hold bonnet switch down if one is fitted. Wait a few minutes after locking to ensure shutdown. Then read the amp clamp, you are looking for 100 mA (0.1A) Max, if any more then start pulling fuses untill drain disappears. Figure out what that fuse does then disconnect components to try and isolate fault. If the drain doesnt go after disconnecting fuses then you will need to disconnect the alternator, then the starter motor as these can cause a drain.

Most common cause is interior lights, radio including accessories, sat nav, water ingress, alternator. Anything that has a permanent supply is suspect but these are the most common. Disconnect any extras like tow bar electrics.

Subscribing!

Had what I thought was a fluke dead battery about a month ago out of the blue.... Figured I must have left a dome light on, or something weird. Fully charged the battery the my CTEK overnight and hadn't had any issues until yesterday.

Parked it at work in the morning, and by quitting time it barely had enough power to crank over and start. No weird dome light issues that I'm aware of.... Full CTEK charge again overnight and today everything is normal again.

Hmmm.....


-G

 

[ChuckB]

I'm having many of the same issues on my '04 LX. I have the rear DVD and also found a LoJack recently which has been removed.
On one occasion that I know of I walked by the Cruiser on the way to the garage and heard what I believe was the passenger front door lock actuator running constantly for who knows how long. Inserting the key in the door stopped it but the truck was dead at that point.

Currently it's at the shop because it's been driving me crazy. I spent an hour today looking around the Cruiser for possible culprits with the mechanic. I'm going to mention the dome light switch and he is looking at the shoddy LoJack wiring.

The latest jump today...

 

[RND1]

Let us know if you figure it out. In the meantime, if it's really driving you crazy, just get a priority start. I paid lots in diagnostic fees to figure out my parasitic draw and while it got better, I still find it dead on occasion if it sits for more than a couple of days. Still drives me a little nuts, but I don't worry about being stranded anymore.

Amazon.com: Priority Start 12-Volt-Pro-SP PriorityStart Automatic Battery Protector: Automotive

 

[ChuckB]

I will look into the Priority Start, thank you.

I forgot to mention that my current battery is 1.5 months old and the Cruiser only sat for 16 hours from being driven to completely dead.

 

[RND1]

I forgot to mention that my current battery is 1.5 months old and the Cruiser only sat for 16 hours from being driven to completely dead.

That was my experience as well. If I recall, my draw was over 500mA to the BAT fuse. When they disconnected the CD changer, the draw went away. I believe the dome light is also linked to the same BAT fuse. I installed an OEM Toyota battery 3 years ago and it's still going with the Priority Start in spite of being completely drained several times.

 

[Velogas]

I have this same demon. On a new battery, if the truck sits more than 36-48hrs it will be dead. I generally drive it daily and it is fine.

 

[ChuckB]

Just following up. At this point there was nothing definitive found. I have resorted to the 2nd row DVD/Dome light in the 'off' position and haven't had any issues in the last week.

If I can keep my kids from playing with the switch, I'm going to call it done for now.

 

[ChuckB]

Well... I'm back to square one... I drove the 73 for about a week and a half straight and didn't touch the 100. I went to go fire it up on Sunday night prior to going to work this morning and it was completely dead to the point I couldn't even unlock/lock the doors with the fob.

I'm ordering the priority start now!

 

[Anthony.L]

I've had a battery drain issue for years and just been lazy and ignoring it by disconnecting the negative lead when the LC sits for a long time. Finally got a good amp/volt meter and did some testing. Google searching ih8mud told me the likely culprit was the CD/DVD changer in the center console. It stopped working within the first year I bought the LC used, so it was definitely suspect.

Checked amp draw with all doors shut and system rested for a while, drawing 500-600mA. Ok there is definitely my dead battery issue. I first pull the 30amp BATT fuse under the hood next to the battery. That drops it all the way down to well under 100mA. So I then pull the 10amp DOME and RADIO fuses in the passenger kick panel fuse box location. DOME didn't do anything, RADIO did the trick. Then I located the locator going to the CD/DVD changer which is directly below the cup holders in the center console. Unplugged that, closed up the doors and let it settle. Checked the volt/amp meter and 23mA draw. Perfect!

 

[agaisin]

Then I located the locator going to the CD/DVD changer which is directly below the cup holders in the center console. Unplugged that, closed up the doors and let it settle. Checked the volt/amp meter and 23mA draw. Perfect!

Can you elaborate on what you unplugged? Just a fuse or a wiring harness? At least personally prefer not to disconnect the entire radio unit but if it's just the changer no biggie. Picture of what was disconnected? How easy/hard to get to the part that needed to be disconnected.

 

[Anthony.L]

Can you elaborate on what you unplugged? Just a fuse or a wiring harness?

I meant to take a picture of the plug I disconnected before I put the center console back together. The plug only feeds (power, ground, and signal) the CD/DVD changer and nothing else. The rest of the radio, DVD navigation, air controls, etc all work as normal. In my case the CD/DVD changer stopped functioning years ago so zero loss disconnecting it.

You want to pull up the center console trim that runs from the cup holders to the dash (around the shift levers, etc). Then look for the connector that is directly under the driver side cup holder. It's about 1" wide white connector with two rows of pins. There is a metal bar running over top it with two 10mm bolts that you can remove to make it easier to disconnect the plug.

 

[Amgaa]

agaisin did you solve ecu-b2 fuse problem? I have same problem with my 2005 lx470

 

[agaisin]

So - I finally got my hands on a data logging multimeter and decided to try and track this down once and for all on my rig. The issue in my case was the rear DVD player intermittently spinning up. I ran many data log sessions and identified some clear patterns of what normal/abnormal draw levels are and how they look over time when graphed. After reproducing the issue on multiple occasions I was able to confirm that the rear DVD player (passenger side third row) was lit and could hear it spinning up when I saw the draw.

In order to reproduce the issue but still have access to the fuses in the engine bay and junction boxes by driver and passenger sides, I latched the hood and also clamped the door sensors. I used voltage drop testing to confirm the 30ABat fuse, and then downstream it was the 10A radio fuse. From there there were only a few options off the 10A radio fuse, but once i saw this thread and the reference to the 7.5A fuse under/behind the glove box it was easy enough to isolate the DVD as the culprit by pulling the 7.5A fuse and confirming. I am going to do more testing over a period of a few days after the holidays, and will provide some followup on this thread, but I was able to identify some clear patterns of normal and abnormal draw behavior under various conditions and this looks pretty clear.

I should mention that I had the car at the dealership a few months ago to try and resolve the issue, they had the master tech looking at it, they had me replace the driver side kickpanel junction box for a total of $2k (they acknowledged they couldn't be sure whether it would fix or not). To my dismay it didn't fix the issue, as the car had died again multiple times even after a new battery - they thought it was . I got sick of this and with some time off around the holidays decided to track it down once and for all. Also confirmed no short or grounding issues and no issue w battery terminals.

A couple of approaches/tools that ended up being indispensable:
1) IH8MUD - the community of knowledgeable dedicated owners/enthusiasts is an amazing resource
2) Voltage Drop Test - the old school approach of pulling fuses is probably fine for situations that are consistently drawing current like a short or stuck relay, but if it's intermittent and related to a computer system you need the car to go to sleep. Without using this approach, pulling fuses means you're starting from scratch each time you pull one. I believe an issue I had in previous attempts at using this approach was that earlier meters I used were not sensitive enough to give accurate mV readings, and I didn't appreciate that when measuring the mV the numbers jump initially before they settle so it looks strange to the untrained eye, like it's unreliable.
3) realizing that even the hood latch need to be closed (used a screwdriver) in order to get the system to behave normally and go to sleep.
4) data logging multimeter (strong preference for Fluke's Trendcapture capability on the 289/287 series) - this made it easy to log data over time and identify patterns - what's normal or not. When using conventional data logging capability you can quickly get into large amounts of data that can make it hard to see the pattern and you waste a lot of time sifting through the data points (all the data logs meters I used were crazy slow so it could take 20+ minutes to transfer a session of 10k data points. With Fluke's trendcapture it really was amazing once I got comfortable with how it works and the settings, b/c instead of logging intervals of 1, 2, 5 seconds I could now use 1 minute or longer intervals, but set 'events' to trigger if the meter value changes more than say 10% of previous stable reading and it will then log those events. Furthermore, I could view the graph immediately to see the pattern rather than having to transfer the data each time. Also - fluke system allows you to track multiple sessions on the meter, and easily track them as separate sessions with associated settings and timestamps so you can easily keep track of what's what.

5) Priority Start deserves credit as well b/c it hasn’t been a showstopper for me over the past 7+ years, just a nagging nuisance in the back of my mind. But was never stranded on account of this issue.

6) top post blade style disconnect switch. Made it easy to disconnect when needed and more important made it easy to Test draw without interrupting things.

Thermal imaging was a dud for me for this use case. I tried very high quality (320x240) thermal imaging and it just didn't seem precise enough with enough resolution to show me the fuses or wires that were active. I liked the form factor of the Extech 540 but can't recommend it for the datalogging capability (or could recommend with some serious caveats), the fluke 28x series was insanely helpful for this - turned it into an almost trivial exercise to capture and analyze the data and easily keep track of it. The flukeview forms was pita and felt like it was industrial software from the 90s (probably is), but it still made it easy (once getting used to the software) to analyze the data across multiple sessions and annotate it to keep track of different sessions easily.

 

[agaisin]

some additional pics of dvd light on (heard noise as well) when the key was out, car was off for hours. Hood latch so I can open/close hood without waking the car system, same for the door sensors.

Also - this post: Parasitic Battery Drain drop down DVD final picture shows the location of the fuse box under glove that allows easy removal of 7.5A fuse to disconnect the problematic rear dvd player.

 

[agaisin]

Steps to reproduce:
1) latch hood
2) clamp doors that you need to get into for troubleshooting. Would suggest at least both passenger side doors but possibly also driver side if your issue may be there. (If you suspect dvd problem, it would be narrowed down to the passenger side junction box cowl)
3) setup a multimeter to read current (10A jack bc at least for the dvd problem it often spikes well above 440mA and consistent readings were ~700mA to ~1.5A).
4) double lock the car
5) Let the car sleep. When I lock the car it went to sleep within ~2minutes. But still it’s good to be sure you have normal draw first so generally you could wait at least 30 minutes and then look for abnormal draw. As this is intermittent It sometimes kicked in immediately, other times after 30 minutes, other times after 4 hours, and sometimes went hours with only normal draw.
Normal is <50 mA. Abnormal is more than 50mA, but at least with my dvd problem the draw was hundreds of mA to over 1A consistent readings so it was clearly an issue. If you have a datalogging multimeter you can just log a handful of 4 hour+ sessions and start to get a feel for the pattern you’re seeing.
6) once you identify an abnormal draw you will (preferably) have a second multimeter to check voltage drop across all the fuses in the main engine bay fuse box or at least have a switch so you can move the multimeter from current to volt settings without waking the car, otherwise you will be chasing your tail. (careful to change the jacks to avoid blowing your fuses). 0mv or like .02mv was normal for voltage drop. There are charts that will convert mA readings off diff size fuses to tell you the draw. Like this one: Power Probe
When your current draw is >50mA you are looking for voltage drop at the same time (hence two meters make it easiest unless you know you are locked in a full on draw (sometimes it spikes up and down quickly i. Which case your volt drop readings may give you a false negative. So for example a reading of 1.2mV on a 30A mini fuse would be 649mA and the same draw would show up as 4.8mV on the downstream 10A Radio fuse. If you suspect the dvd issue then you could start w the volt drop on 30A bat fuse and then follow up on the 10a radio fuse and then look for the glow on rear dvd and listen for sound. If that’s your problem the fix is easy - just look for the 7.5A Inline fuse forndvd under glove box and pull and confirm drop in draw down to <50mA. In this case pulling the 7.5mA fuse does not appear to wake up the car (alarm didn’t go off).

Hope this helps others!

 

[offbrandLC]

Thanks All for your contributions! I was running out of time but had all the symptoms seen in this thread (150mA sleep mode draw, traced to ecu-b2 ckt but no apparent sub system being the cause). Was heading out to an Ozark wheelin weekend so brute forced the Disc changer unplug solution and so far it looks like I got lucky and no drained battery in 4 days including 2 cold nights in the Ozarks. Never even used the darn thing, but fingers crossed that was it!

Side bonus driver seat warmer started working by the dissembly/cleaning/reassembly of the center console!

 

[Turd Furgeson]

This thread was really helpful, especially @agaisin, great notes on the hood latch and letting the car get to sleep. Wonder if anyone can help me with my final step.
I've got a 2006 LC, have parasitic draw of 190ma that I traced to ECU-B2. I started looking for specific system and I think I found it in the master door switch. Side note, I've never been able to get the blinking light of the drivers door to remain on steady. The auto up/down has never worked correctly despite all other doors working fine.
When I unplug the master door switch, the parasitic draw is gone, down to 30ma for the whole vehicle.
I've tried replacing the master door switch with one from Switch Doctors, no change.
Is there something with door switch I should consider swapping out to fix this?

While trouble shooting this auto up/down i replaced a non-OEM door motor with an OEM door motor. Still no change. I'm stumped.

 

[dRo15]

This thread was really helpful, especially @agaisin, great notes on the hood latch and letting the car get to sleep. Wonder if anyone can help me with my final step.
I've got a 2006 LC, have parasitic draw of 190ma that I traced to ECU-B2. I started looking for specific system and I think I found it in the master door switch. Side note, I've never been able to get the blinking light of the drivers door to remain on steady. The auto up/down has never worked correctly despite all other doors working fine.
When I unplug the master door switch, the parasitic draw is gone, down to 30ma for the whole vehicle.
I've tried replacing the master door switch with one from Switch Doctors, no change.
Is there something with door switch I should consider swapping out to fix this?

While trouble shooting this auto up/down i replaced a non-OEM door motor with an OEM door motor. Still no change. I'm stumped.

@Turd Furgeson Did you figure this out? I have the same exact issue with the ECU-B2 fuse draw and master door switch (blinking light and auto up/down not working). I also replaced the master door switch with non-OEM version.

 

[Turd Furgeson]

@Turd Furgeson Did you figure this out? I have the same exact issue with the ECU-B2 fuse draw and master door switch (blinking light and auto up/down not working). I also replaced the master door switch with non-OEM version.

That fixed it for me! I found one on eBay, I think it was like $100. Immediately fixed the draw, I was stunned by how much that bad switch was drawing. So hopefully you get resolution. Keep me posted.