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To continue on this thread. The problem reared its ugly head again. Left it alone after seeing the ma down to 38, for 6 days. Checking voltage daily but didn't the last couple of days. It was at 10.8 volts. I put the meter inline again and saw .8 amps and waited, it didnt go down much, so I unplugged the door controls again (both fronts) and it eventually settled to 150ma. I noted that the door locks didnt work with the remote now, wouldn't lock or unlock with the door controls back in place. Guess Im back to square one.
After living with this problem with my '99 for 6 or 8 months, I finally got something right. I read this forum with interest, pulled fuses and made measurements and generally cursed a lot. I could pull two fuses and drop the draw considerably but not completely. So I changed tactics and worked on known problems.
My driver's window switch was acting flaky, so I replaced it. No good on the voltage drain. In experimenting around I discovered that the passenger door did not work the overhead light. So I replaced that window switch unit, also. No joy. But when I commented about this to the mechanic who sold the switch to me he suggested that I change the door module. So about $13 and some headaches later (not as easy as the videos show) the door once again operates the light.
AND my voltage drain problem is cured! I can park it for 6 days and it still starts!! Haven't had the nerve to go further than 6 days... I'm just happy with the result. SO... Check those door modules!!
You didn't happen to check to see if the new switch did anything relative to the dome light operation? I wonder if the switch and module could
operate the light, but the module still drain the battery?
My windows work fine, but I guess this is not evidence I don't have a bad module?
I had a Mercedes C Class where the seat module worked perfectly, but it would sometimes drain the battery.
If I remember correctly the car will still run and only unhooks everything downstream from the Short Pin as shown.
Let me know if you need a pic of the actual Short Pin and plz let us know what you find.
I have been lazy and just have been using a battery tender to keep my battery up during periods I don't drive my car, but I am moving where I won't have a power source to power the trickle charger.
Do you remember with the "Short Pin" pulled if he remote door locks work? I imagine I will lose my clock memory and the radio station memory, however.
I ordered a smallish Solar charger to hook to he battery to keep it from going flat. Unfortunately our dash power plug is disabled with the key in he "off" position, or I'd plug he solar unit in there and put he charger on he dash. Lacking that I suppose I can connect it with Zip Ties to the narrow grille section under the bottom of the hood and connect it directly to the battery terminals all of he time. My battery doesn't go flat overnight, so hopefully the 1.8 watt charger (150ma) will replenish the battery by daylight charging alone when the car is outside for long periods unused.
I will now need to get serious about finding/fixing the problem.
My battery doesn't go flat overnight, so hopefully the 1.8 watt charger (150ma) will replenish the battery by daylight charging alone when the car is outside for long periods unused.
I will now need to get serious about finding/fixing the problem.
It will work as long as your parasitic draw is below 125ma ... just added a bit of margin.
My battery never goes flat in less than 2 weeks if the car is not used.
If it kills 75% of a 100 amp hour battery, that would mean 75 amp hours in 2 weeks (336 hrs), so 75ah = 1000 = 75,000 mh-hrs/336 = 223 mh draw average.
If the solar charger supplies 150ma for 12hr a day (in AZ Sun), or 75ma avg over 24hr period) that would reduce the drain overall by at least a third (223mg - 75ma avg), so the battery should at least start the car up to 3-4 weeks vs only 2wks.
They make a 5w charger, but it was too large to mount externally, though if I hooked it to the bat and put it on my car's dash when not driving, it would do nicely I suspect.
Had to update previous post because it can get a little confusing.
The Body ECU has 3 power wires from different fuses that appear to power the Body ECU differently depending on what mode it is in- Key on ACC, Key on IGNITION, or off.
Turns out the ECU-B fuse does also go to all 4 doors too, found that on a different page. I believe the ECU-B is the Body ECU power wire for when the key is off.
If I was leaving it somewhere I would unhook the battery altogether.
-> Here is the year 2002 RX300 detail for the Short Pin and showing some power distribution. On the RX330 it is in the fuse box under the hood and labeled, hope yours is too.
Procrastination...
Just went looking for my SHORT PIN in the fuse boxes but saw nothing labeled on my '03 RX300.
I am attaching photos of the Fuse Box labels to see if it is THERE, but not shown on my Fuse Box Cover.
Sorry I don't have it handy. A quick search on eBay has multiple hits. Feel free to call local Lexus parts or dig through Lexus on line retailer [Lexus of South Atlanta etc]. It is your option to buy from who ever, but beware of copies and 2nds.
After living with this problem with my '99 for 6 or 8 months, I finally got something right. I read this forum with interest, pulled fuses and made measurements and generally cursed a lot. I could pull two fuses and drop the draw considerably but not completely. So I changed tactics and worked on known problems.
My driver's window switch was acting flaky, so I replaced it. No good on the voltage drain. In experimenting around I discovered that the passenger door did not work the overhead light. So I replaced that window switch unit, also. No joy. But when I commented about this to the mechanic who sold the switch to me he suggested that I change the door module. So about $13 and some headaches later (not as easy as the videos show) the door once again operates the light.
AND my voltage drain problem is cured! I can park it for 6 days and it still starts!! Haven't had the nerve to go further than 6 days... I'm just happy with the result. SO... Check those door modules!!
What was your part number for the door module?
I believe that I have the same issue, having inherited a 2001 RX300 with 100,200 miles on it...with a trickle charger thrown in (for good measure ). I have not done any troubleshooting, but have observed inconsistent issues with the remote locking and the headlights not turning off. Also noticed that the dome light does not work! Didn't know if this is the actuator or module brain. Thank you!
2001 RX 300 Battery Drain Diagnosis done.
Lots of panels removed. Gauge cluster is the culprit.
Of course that part is obsolete 23 years later.
Great work to narrow down what has failed for you. There should be plenty of cluster units in salvage yards. Only thing to keep track is the odd meter reading. Some models of Lexus from that era had the odo value stored on chip in the cluster.
Take away for the novice DIYers ... Cluster is just one of the possible excessive drain location. So do the testing to confirm.
10-18-21, 07:07 AM
). I have not done any troubleshooting, but have observed inconsistent issues with the remote locking and the headlights not turning off. Also noticed that the dome light does not work! Didn't know if this is the actuator or module brain. Thank you!
