When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi all, I've been doing a lot of lurking the last few weeks, and reading a lot of My.IS and ClubLexus posts about parasitic drain problems on these cars. Backstory is this is my wifes car, she has owned it since new and it's been stored outside in NYC area since new. Recently it was moved to my parents' house (we live in Manhattan and just keep one car in the city) and while parked there during Covid, the two drain plugs in the front of the sunroof clogged, and water leaked into the drives side of the cabin, enough to make the carpets wet. Had some issues with the electronics and the car, and took it to a trusted indy mechanic in my hometown. Also, car has 42,xxx miles on it, so it's basically mint and was always well maintained.
First we put in a new battery, and he checked the codes, and said it needed a new steering position sensor and he cleared out the drain plugs to prevent more water seepage. We did that, it was "done", and then 3-4 days later still having major issues driving it and the car dying in a day or two of sitting. So we take it back, he checks, and says it needs a new steering ECU (I forget the correct/proper term) and we do that. Car works, but then doesn't work and is dying after a few days. At this point, we're having issues with the drivers door switches not working, heat not blowing hot, and the car doing "machine gun" clicking after sitting for a few days with a dead battery. Take it back to him, and the battery is bad - so it's replaced under warranty (Thanks Interstate) and he blows out the heater core, and it's all working again but the door switches. So I take it home, and dry it out with rechargeable dehumidifying packs and a giant Viper water spill blower for a few days in the sun. Car continues to dry and sit, and it's fine. Eventually after a week or so, the door switches work again fine, but the car dies after 2-3 days of sitting and not being run or trickle-charged at all.
Finally, I get fed up with it and today I busted out a brand new digital multimeter (my old one broke) and set about testing. Car has 12.5-12.6 volts on the battery while off, and 14.2-14.2 while the car is on and running - so I know the battery cells haven't gone bad yet, and that the alternator is at least generating current correctly.
So, I unplug the neutral wire on the battery, set up the multimeter to the 12v battery setting, and connect to the negative battery terminal and the ground cable wire connector, and see 12.62 to 12.22 of current drawing on the car while the battery is disconnected. Then, I start pulling every god damned fuse in the 4x boxes (two in engine bay, and one each under drivers/passengers dash) and the most I see the drain drop to is 10.31 after pulling one or two fuses in the fuse box right next to the battery. Nothing clearly solving the whole problem.
I would LOVE and appreciate any advice or tips on where to look for further diagnosis or how to potentially solve this. My wife is incredibly sentimental about this car, and after a really ****ty year (like everyone has had) she can't bring herself to just write the car off and sell it. I'm just trying to be a good husband and salvage what I can from this, without spending an arm and a leg on an 11 year old Lexus we barely use. In the interim, I've ordered a waterproof black and decker battery tender/trickle charger and a waterproof extension cord connector cover, and plan to set the car up to trickle charge either through the 12v socket inside the car, or just right to the terminals under the hood, so it's usable and I don't trash another brand new Interstate battery.
Worth noting, I'm a BMW fanboy myself, and don't do a lot of wrenching. I have some basic tools and basic knowledge, but anything overly advanced would lead me to just going to a mechanic. But, having some tips for him to triage and check in a rapid-fire way could also allow me to fix it or isolate the problem while minimizing my mechanic costs. And if anyone has an awesome Lexus indy/specialist on Long Island (nassau county preferred) I'd be super open to recommendations to try and see if that fixes it fast.
Thanks for reading, and thanks in advance for any advice you all can give.
Pic of the multimeter with the fuse out that made the drain go down:
Hi all, I've been doing a lot of lurking the last few weeks, and reading a lot of My.IS and ClubLexus posts about parasitic drain problems on these cars. Backstory is this is my wifes car, she has owned it since new and it's been stored outside in NYC area since new. Recently it was moved to my parents' house (we live in Manhattan and just keep one car in the city) and while parked there during Covid, the two drain plugs in the front of the sunroof clogged, and water leaked into the drives side of the cabin, enough to make the carpets wet. Had some issues with the electronics and the car, and took it to a trusted indy mechanic in my hometown. Also, car has 42,xxx miles on it, so it's basically mint and was always well maintained.
First we put in a new battery, and he checked the codes, and said it needed a new steering position sensor and he cleared out the drain plugs to prevent more water seepage. We did that, it was "done", and then 3-4 days later still having major issues driving it and the car dying in a day or two of sitting. So we take it back, he checks, and says it needs a new steering ECU (I forget the correct/proper term) and we do that. Car works, but then doesn't work and is dying after a few days. At this point, we're having issues with the drivers door switches not working, heat not blowing hot, and the car doing "machine gun" clicking after sitting for a few days with a dead battery. Take it back to him, and the battery is bad - so it's replaced under warranty (Thanks Interstate) and he blows out the heater core, and it's all working again but the door switches. So I take it home, and dry it out with rechargeable dehumidifying packs and a giant Viper water spill blower for a few days in the sun. Car continues to dry and sit, and it's fine. Eventually after a week or so, the door switches work again fine, but the car dies after 2-3 days of sitting and not being run or trickle-charged at all.
Finally, I get fed up with it and today I busted out a brand new digital multimeter (my old one broke) and set about testing. Car has 12.5-12.6 volts on the battery while off, and 14.2-14.2 while the car is on and running - so I know the battery cells haven't gone bad yet, and that the alternator is at least generating current correctly.
So, I unplug the neutral wire on the battery, set up the multimeter to the 12v battery setting, and connect to the negative battery terminal and the ground cable wire connector, and see 12.62 to 12.22 of current drawing on the car while the battery is disconnected. Then, I start pulling every god damned fuse in the 4x boxes (two in engine bay, and one each under drivers/passengers dash) and the most I see the drain drop to is 10.31 after pulling one or two fuses in the fuse box right next to the battery. Nothing clearly solving the whole problem.
I would LOVE and appreciate any advice or tips on where to look for further diagnosis or how to potentially solve this. My wife is incredibly sentimental about this car, and after a really ****ty year (like everyone has had) she can't bring herself to just write the car off and sell it. I'm just trying to be a good husband and salvage what I can from this, without spending an arm and a leg on an 11 year old Lexus we barely use. In the interim, I've ordered a waterproof black and decker battery tender/trickle charger and a waterproof extension cord connector cover, and plan to set the car up to trickle charge either through the 12v socket inside the car, or just right to the terminals under the hood, so it's usable and I don't trash another brand new Interstate battery.
Worth noting, I'm a BMW fanboy myself, and don't do a lot of wrenching. I have some basic tools and basic knowledge, but anything overly advanced would lead me to just going to a mechanic. But, having some tips for him to triage and check in a rapid-fire way could also allow me to fix it or isolate the problem while minimizing my mechanic costs. And if anyone has an awesome Lexus indy/specialist on Long Island (nassau county preferred) I'd be super open to recommendations to try and see if that fixes it fast.
Thanks for reading, and thanks in advance for any advice you all can give.
Pic of the multimeter with the fuse out that made the drain go down:
hey buddy, I know why your door switches weren’t working, assuming it’s all door switches but the drivers side front door window. If so, then it’s because when you replugged back in your battery you didn’t do the special Toyota/Lexus window procedure where you must do this special thing and do it on each doors switch, and then turn off the cars ignition completely then back on.
now if all switches died no matter which door you’re operating the window from then I would imagine it would be a bad fuse or an old fuse. Even an old, semi dying fuse can add a “load” to your electrical system, causing your battery to drain over time (like in a few days). Kind of how a nail in the tire but one thats barely leaking, would give you a flat but you wouldn’t notice it until 2 mornings later in the garage.
I would replace the fuses if they are somewhat affordable for good measure and/or I would get the red colored DeOxit spray or liquid with the brush applicator and use it to clean every electrical contact in the fuse box and battery and fuses themselves. I also would “deoxit” the electrical plug that powers the electric fan located in the front part of the engine closest to the headlights, behind the radiator. Lastly I would also make sure your gas cap and oil and radiator caps are fully sealed without any abnormal back pressures hidden inside.
also if it were me, I’d buy a can of redline fuel system cleaner and let it just sit in the gas tank if I wasn’t going to drive it for a few days.
hope this helps but yeah I think strong possibility a fuse that’s really old or dusty or corroded is loading down the electrical system ever so slightly. Feel free to pm me I’d be happy to give ideas and or help if I have the knowledge that may be useful.
the most I see the drain drop to is 10.31 after pulling one or two fuses in the fuse box right next to the battery. Nothing clearly solving the whole problem.
It would take a higher end meter to measure current, it appears OP is measuring battery voltage between the disconnected terminals which isn't going to tell you much on a modern car. You'd have better luck with 12v lightbulb, not an LED as they draw very little current.
Next issue is these cars keep a lot of items alive so for example the navigation shuts down to lower and lower levels over time. So reconnecting the battery starts processes that draw current.
That said, you are on the right path regarding pulling fuses and measuring current but you need the right tools. Mind you the surge of current (sparks seen) when connecting the battery is in excess of 10Amps and will blow the fuse on most meters so you can't just casually place the meter in line or damage will occur if it's not rated for say 50 amps (guessing). That said, there is a simple way, you start with the cable on the battery while having your meter leads on the post and cable. Once the in rush current is over, lift the cable allowing the meter to take the load.
If I had to guess, I'd bet someone reversed the battery polarity and it damaged something putting this parasitic drain in motion. Try disconnecting the amp in the trunk and use a light bulb for a load if don't have an amp meter.
Oh, doesn't make sense to measure voltage like that. I don't think connecting the battery will generate 50 amps. I think it will be much less than 10 amps as nothing uses that much power unless you start turning on the accessories.
Oh, doesn't make sense to measure voltage like that. I don't think connecting the battery will generate 50 amps. I think it will be much less than 10 amps as nothing uses that much power unless you start turning on the accessories.
I'm saying it may only last a nanosecond but I've seen 10 Amp meter fuses blown from just inserting it cold even though once connected and stabilized, it only draws 3.0mA or less.
Lets say the battery in question is good for 75AH, a draw of 1.5 Amps would kill it in 48 hours no problem but its initial connection that would kill some meters. That said, I've never seen a published current draw on what it should be. Likely in the neighborhood of 0.5 to 0.75mA??
OP - even though the alternator works and shows good output, you need to have the diodes tested as they can leak drawing current but still rectify AC to DC.
I found an old thread of mine that I had measured the car to be 2.2 amps on reconnect. If I remember it correctly, it drops to the mA range after a while. But if there is something wrong with the car and some components are shorted, I can see the current draw be high enough to blown meter's fuse.
My one and only electrical issue (sort of "drain" related) was my trunk lamp mechanism started not shutting off when clearly flipped OFF. So now it is unplugged and I have no light in the trunk. LOL!
11-20-20, 04:37 PM
09 IS 250 - Parasitic Drain Issues
