I have an 2004 rx 330. I have the weirdest problem and cannot diagnose it. Any help here would be so much appreciated. My RX330 discharges when it is humid or raining out. When its dry it works fine.
I have been through 2 batteries and now also have a brand new alternator.
It works fine then randomly and suddenly the battery dies. I mean it goes from fully working and fully charged to 0-3 volts overnight. I have made sure I am not leaving any little light on or anything is left on overnight. Im positive of that. I have thought it was a slow drain through the alternator but that is also brand new now. I have been through 2 brand new batteries as well.
Is it possible there is some wire somewhere on the car that is shorting out only in humidity and rain? If so, how in the world would I find that wire/wires location?
This is the most frustrating problem I have ever had. Has anyone heard of this happening. I am no electrician myself but do have some understanding of current and such. What could be draining a battery THAT FAST without heating up the battery or some part of the car. I just dont get it.
After I recharge the battery it works fine for a while and then it happens again. Of course it kills the battery going down that low so I have had to replace it twice.
I have also checked that the voltage from the alternator is good. Usually around 13.9-14.5 when driving the car.
HELP HELP...

 

You start by putting your amp meter in series to see the current (at battery, and even alternator cable to check it), (seems like it must be several amps when it is happening, use a garden hose to wet it down to get it going if dry), and then start pulling fuses one by one until the current drops to identify the circuit. Then go wire hunting...

 

Can you give a little detail on how to hook up the amp meter in series as you have said? I'm at a very basic level of knowledge, I do have an amp meter. Can you give a little more?
Am I looking for the amperage to go up or down when I pull the fuse in the circuit which has the short?

 

Do you have anything aftermarket? Like remote start, alarm, radio, trailer controller, etc?

To test for parasitic draw, car needs to be fully off. Pick your poison, remove either the positive or negative terminal of the battery. Put multimeter in current draw mode. Then connect and isolate the wire you chose to one probe of the multimeter and the other probe to battery terminal. You basically put it inline between the battery and the battery terminal.

There are a few grounds in this car, check all of them for corrosion, split wires, or damaged ends.

 

Good ideas already posted.

Just curious how long you've owned the vehicle & miles?

 

Thanks for the details I will do as you wrote to try and find a draw on the battery.
There are NO other additional add ons with this car. It is completely stock.
Car owned for about 7 months. Has 280k on it.
I know original owner who babied this car so i intend to get 500k on it.

 

Hi Brucecav, just a courtesy follow up to see if you got it figured out.

It may be nothing but just thinking-
I always keep a voltage meter always plugged in my cigarette lighter and when I start my car it is may be near 13.9V when first started in morning but it is rare to get into the 14'sV unless I don't start my car for a few days or a week but I don't have any parasitic drains pulling my battery down over night.

After driving a while it goes down near 13.5V after battery charges up.

 

Not fixed yet but made some progress. Connected in amp meter in series with the battery and there appears to be a .5 amp drain on battery which I understand is way higher than normal. I believe the normal amperage drain on a battery that is sitting is .1 to .2amps, correct me if I'm wrong. I'm new to all this and trying to figure out this problem. The next step is to connect the amp meter in series and start pulling out the fuses one by one to find out which fuse circuit is causing the draw on the battery.
The car is completely stock and there is no new items on it that could potentially be causing the drain.
If you have any other ideas or suggestions please let me know. I am open to all help from anyone who has ideas. Currently the task ahead of me is huge and even after I find the circuit that might be drawing the battery down it may be very difficult to find where in that circuit there is a short.
Thanks
Bruce

 

This is the fastest way.

I'd start with "Dome" & "ECU-B".

 

It was my ECU-B.. I have a strange fix but its working fine so far. see the details in my post under the more recent question about a parasitic draw on an rx-350.
VERY INTERESTING WHAT I DID

 

Thank you for sharing your fix, it sounds like you are almost there.
>> Pulling ECU-B fuse also cuts battery power to other things.


Pulling ECU-B cuts battery power to "Power Window Master Switch"(pin 9).



Also cuts battery power to "Door Control Receiver" which is located at "top of left D pillar"(pin 5).




Also cuts battery power to Dash Cluster/Combination Meter(Plug A, pin 15).

 

Is it possible that some water was pooling at the spot near the map light and its corroded something so its always on and drawing power thats why it works without the fuse? Idk if you live in an area that experiences salty roads, or if that is possible just trying to help you figure out the root cause of the issue.

 

Thanks. I will check that for sure.
Would that be the map light in the back, cuz i do know that water gets into the back hatch at times. it fogs up my rear tail lights. After a hard rain water pours out the hatch door when I lift it up. Could that be related??

 

My dash and all instruments are working fine without the fuse in .
this is so weird.

 

That may have something to do with it there is a little "bowl" that diverts the water for the sunroof if my understanding is correct when it rains sometimes if that "bowl" has stuff in it it will make the water pour in through the map/dome light in the front I have actually physically watched water come in but its only on a certain degree of hill that the water comes in, so there is a good chance it could be traveling backwards and flooding the tailgate or there is something similar that is allowing water to pour in and corrode something.