Parasitic Draw - Fuse identified… (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Sep 16, 2020
Threads
1
Messages
13
Location
Atlanta, GA
Hello,
My 2010 lx570 recently died overnight despite new battery. Identified a significant draw on my meter and isolated it to 3 different fuses all pointing to the same general system but I am unsure what to do from here.

Concerns that led up to the dead battery:
The rear tv has not worked since we bought it a year ago.
The USB outlets up front don’t charge the phone.
The key fob stopped working so I replaced the fob battery but it still didn’t work.
The next day the battery died.
Replaced the battery and it died overnight which led me to the parasitic draw.

The fuses showing the draw: 10A TV ; 7.5A RSE ; 10A RAD NO. 1.
E87BE888-D328-407C-ABF1-53E807B6FC81.jpeg


All fuses point to the same systems:
Audio System, Multi-Display, Lexus Nav system and Parking Assist (Rear View Monitor)
841618F0-2A9F-4CAF-B99F-BB2F82B3F1FC.jpeg
843CAE3C-4D03-4C42-B6B5-DEFE93E1AD79.jpeg

How do I go about diagnosing from here?
Any advice would be greatly appreciated.
Thanks,
Mitch
 
How much draw are you measuring? Does pulling any or all of those fuses fix the dead battery issue?

If the isolation to that component is correct, can you confirm the device is actually turning off or going to standby with the engine off?
 
A couple further questions……Have there been any aftermarket modifications to electrical components like remote start or audio equipment? Has there been any water inside from things like leaking replacement windshields or plugged sunroof drains? Any history of flooding? You’ve mentioned a number of symptoms besides parasitic drain, including getting worse over time, so I might start by looking for something affecting connectors.
 
How much draw are you measuring? Does pulling any or all of those fuses fix the dead battery issue?

If the isolation to that component is correct, can you confirm the device is actually turning off or going to standby with the engine off?
Thank you for the reply!
It was a 9 Amp draw.
I pulled all relevant fuses and it still died. 😬

When I turn off the vehicle chimes constantly as if my lights are on.
 
A couple further questions……Have there been any aftermarket modifications to electrical components like remote start or audio equipment? Has there been any water inside from things like leaking replacement windshields or plugged sunroof drains? Any history of flooding? You’ve mentioned a number of symptoms besides parasitic drain, including getting worse over time, so I might start by looking for something affecting connectors.
Thank you for your reply and questions.
No aftermarket mods.
I haven’t noticed any water but I did notice condensation on inside of windshield over the summer.
No flooding that I’m aware of.

Is the dash relatively easy to open and start pulling trim? That sounds like my next step!
 
Do you have any phone chargers in the cigarette lighters? If so, take them out immediately.
Not in cigarette lighter but sure as hell is one in the usb outlet… I assume same problem? Will it still draw without anything connected?

Thank you for the reply.
 
I haven’t noticed any water but I did notice condensation on inside of windshield over the summer.

That sounds like there may be a leak.

Is it the original windshield or has it been replaced?
 
Not in cigarette lighter but sure as hell is one in the usb outlet… I assume same problem? Will it still draw without anything connected?

Thank you for the reply.
You would notice if your usb plug was pulling 9amps at 12v....you'd have a mini space heater in your console., more likely a fire.

After pulling those 3 fuses, do you still have a parasitic draw? Hard to imagine your battery would keep dying after removing the 100watts of constant drain. Unless you battery is compromised, which is possible considering your issues.

If it's water in the body connectors, you should start by pulling the A Pillar lower trim.

First remove the door sill plates (the plastic bits with the Lexus letters lit up) on driver and passenger side, they are held on by clips, just pull them up and towards rear of vehicle. Unclip the lights and remove.

Passenger Side:
On passenger side, remove the black plastic cover under glove box. It's has 4 or 5 recessed clips that you engage by shoving your fingers in along the front edge. Then just swings down and pulls out. It has at least one light to unclip and possibly a glass break sensor, unclip that and remove the cover.
Now you can remove the outer kick plate along the A pillar. All clips and one slide on nut in the corner near the firewall. Pull (twisting helps a little) the nut. Most of the clips are along the edge of the panel closest to the door, so pry from that side. Then pull the plate towards center console away from the a-pillar and then towards you.

Drivers Side:
I'm not sure if I've removed this side. I know it's similar, but I think it takes more work to get the panel from under the steering wheel off. I think there are a few screws on that side. Other than that, it's the same. (It's been a while, but I think I was able to get the kick panel off without removing the cover under the steering wheel, but i had to be pretty aggressive with bending plastic to get things around parts. It would be better to remove the panel. )

Once the panels are off, the main wiring harness connection points will be exposed. These are the most common places that water gets and starts fouling up electronics. You'll either be looking for moisture or corrosion from moisture. The corrosion is usually greenish in color (oxidized copper).

Here's a picture of the passenger side. The connectors are on the right. The green arrow is pointing at them, I stole this picture form the thread where I was chasing down a leak.
Notes:
You have to remove the trim pieces along the console if you want to pull the carpet back like this in the picture.
You shouldn't' need to for just checking for water in the area.
The carpet has a water proof barrier, so if water was leaking from around the carpet and getting under it, don't assume because the carpet isn't wet that there is no water behind it.
Leaky sunroof drains and windshield frames probably don't result in wet carpet because the leak flows down the frame behind the A pillar plastics.

wet-areas-and-plugs-jpg.2546367
 
Seems like everything is pointing to water damaged electrical connections. Moisture condensing inside and goofy electrical effects. Start with the excellent notes by @lx200inAR and find the water and corroded connectors. Also run a search on here for same. Many others have had inside water causing problems, including @Markuson
 
sorry I have no good advice but I was wondering what book is that you are using? FSM?
I have pdf version of my FSM but that looks like a great hard copy reference
 
sorry I have no good advice but I was wondering what book is that you are using? FSM?
I have pdf version of my FSM but that looks like a great hard copy reference
Not sure if it's what he has, but early on in the 200 lifespan, there were printed FSMs.

They were made by Helm Publishing. You can still order some of it from a 2009.

 
You would notice if your usb plug was pulling 9amps at 12v....you'd have a mini space heater in your console., more likely a fire.

After pulling those 3 fuses, do you still have a parasitic draw? Hard to imagine your battery would keep dying after removing the 100watts of constant drain. Unless you battery is compromised, which is possible considering your issues.

If it's water in the body connectors, you should start by pulling the A Pillar lower trim.

First remove the door sill plates (the plastic bits with the Lexus letters lit up) on driver and passenger side, they are held on by clips, just pull them up and towards rear of vehicle. Unclip the lights and remove.

Passenger Side:
On passenger side, remove the black plastic cover under glove box. It's has 4 or 5 recessed clips that you engage by shoving your fingers in along the front edge. Then just swings down and pulls out. It has at least one light to unclip and possibly a glass break sensor, unclip that and remove the cover.
Now you can remove the outer kick plate along the A pillar. All clips and one slide on nut in the corner near the firewall. Pull (twisting helps a little) the nut. Most of the clips are along the edge of the panel closest to the door, so pry from that side. Then pull the plate towards center console away from the a-pillar and then towards you.

Drivers Side:
I'm not sure if I've removed this side. I know it's similar, but I think it takes more work to get the panel from under the steering wheel off. I think there are a few screws on that side. Other than that, it's the same. (It's been a while, but I think I was able to get the kick panel off without removing the cover under the steering wheel, but i had to be pretty aggressive with bending plastic to get things around parts. It would be better to remove the panel. )

Once the panels are off, the main wiring harness connection points will be exposed. These are the most common places that water gets and starts fouling up electronics. You'll either be looking for moisture or corrosion from moisture. The corrosion is usually greenish in color (oxidized copper).

Here's a picture of the passenger side. The connectors are on the right. The green arrow is pointing at them, I stole this picture form the thread where I was chasing down a leak.
Notes:
You have to remove the trim pieces along the console if you want to pull the carpet back like this in the picture.
You shouldn't' need to for just checking for water in the area.
The carpet has a water proof barrier, so if water was leaking from around the carpet and getting under it, don't assume because the carpet isn't wet that there is no water behind it.
Leaky sunroof drains and windshield frames probably don't result in wet carpet because the leak flows down the frame behind the A pillar plastics.

wet-areas-and-plugs-jpg.2546367
First of all... Thank you for taking the time to spell this out for me. I went down the rabbit hole fairly confidently as a result of this post and it looks like you are dead on. At least a few of the problems must be attributed to what I discovered where you advised to look:
The driver's side was far worse than the passenger side. Passenger side is where I started and found some indication of mild corrosion on one area but I had to really get in there to see it.
Here's that one:
Corrosion wiring - mild - right side.png

The Driver's side was much worse and are those burn marks?
corrosion wiring.jpg

corrosion wiring 2.png

Corrosion wiring 3.png

lx570 corrosion .png


Could these cause the large draw I'm seeing on the battery? Should I keep pulling trim pieces and checking behind the nav unit?
THanks again for all the help with this. Much appreciated.
Mitch

BTW... the book is a 2010 lx570 electrical wiring book. it looks like a reprint from someone as there is no color and a lot of the circuites mention shading of different colors to indicate junctions vs relays, etc. I'll post a picture of the book when I get a chance tomorrow.

corrosion wiring.jpg
 
That sounds like there may be a leak.

Is it the original windshield or has it been replaced?
Thanks for the reply Studawg, It appears to be an aftermarket/replaced windshield. Could that cause leaks in the pillars or somewhere else?
 
Thanks for the reply Studawg, It appears to be an aftermarket/replaced windshield. Could that cause leaks in the pillars or somewhere else?
Yes. A poor windshield replacement job can result in leaks where you are finding corrosion.

The connectors can be saved with careful cleaning and use of dielectric grease. I’ve used contact cleaner soaked q-tips for that type of thing, but others on here will chime in with better ideas.

No need to pull trim for behind the dash/nav. The leaks are going to cause problems right where you found them.
 
Yes. A poor windshield replacement job can result in leaks where you are finding corrosion.

The connectors can be saved with careful cleaning and use of dielectric grease. I’ve used contact cleaner soaked q-tips for that type of thing, but others on here will chime in with better ideas.

No need to pull trim for behind the dash/nav. The leaks are going to cause problems right where you found them.
That's a bummer regarding the windshield. I'll need to rectify that here soon. Regarding the connectors...I'm seeing some black charred looking residue...Is that likely burn marks or corrosion or both?
Thanks for the reply!
Mitch
 
That's a bummer regarding the windshield. I'll need to rectify that here soon. Regarding the connectors...I'm seeing some black charred looking residue...Is that likely burn marks or corrosion or both?
Thanks for the reply!
Mitch
Also check the sunroof drains. Do that before you do windshield work.


I don’t think those are burned connections. It’s possible, but it looks more like corrosion. Hopefully someone with more connector cleaning experience will chime in here soon.
 
Yeah, hard to tell from pictures. My first step would be to get some electronics cleaner and clean it all up. If all the "color" goes away and the plastic looks like it's still in good enough shape to make connections, I'd run it and see if you issue is resolved.

Was damp in there now? I second checking sunroof drains before going too deep in on the windshield.
 
In my uneducated opinion that blue connector was the cause of your blown fuse. The green stains are copper salts that are conductive and wash out of the connectors and cause short circuits while the black is burnt/melted plastic and possibly metal. To get hot enough to melt either takes a pretty heavy draw and it wouldn’t surprise me that those connections turned out to be unrepairable and will have to be replaced in a worst case situation. I’ve used q tips, wire brushes, toothbrushes, plastic brushes and toothpicks to try and clean up those connection blocks as well as spray cans of contact cleaner, even brake cleaner and some other “green” cleaner before brushing on some dielectric grease. All of that green corrosion has the potential to be another path for a short so you have to get rid of as much as possible.
On the burnt connectors, I would try to scrape away as much of the “black” that I could, maybe a welding tip cleaner or dental pick, to get to shiny metal so that you have good metal to metal contact. If you use some sort of contact grease you have to make sure that you don’t create more shorts by smearing it around, I’m a klutz so I avoid using it.
 
If the problem is extensive you can removed the terminals from connectors using specialty tools (amazon or ebay); instructions on YouTube. That will give you more access to each individual terminal for cleaning.

Toyota dealers also have access to connectors for harness repair (at least that was the case with older Toyota's and the factory 2002 Harness Repair manual has 414 pages).
 

Users who are viewing this thread

Back
Top Bottom