Severe Delayed Batter Drain...

[primetime4]

Hello All... I am new here although I have been lurking for a few months now. This forum has been a tremendous resource and a big part of why I was excited to recently join the Land Cruiser community. I know that this topic is regularly reoccurring and I have read just about every thread on this issue but my LC has a little twist that I am hoping for some additional feedback on.

I recently purchased a 2001 LC about 3 months ago. Mechanically and cosmetically, this thing is a dream. exactly what I have wanted for a long time and I am thrilled to own. The only issue I have with it is if the truck sits for 2.5 days, the battery is dead. This happens like clockwork. I have had it into two different dealers (1 had it for 7 days and the other for a few hours) and neither were able to detect any sort of abnormal draw. I believe the reason for this might be because the parasitic drain does not seem to kick in until after 2 days of sitting but is definitely strong enough to kill the battery by day 3. The dealers I believe were checking this within the first 2 days and did not find anything or were starting to vehicle to check it every day after which the countdown "clock" seems to reset. If I drive the truck everyday, there are absolutely no issues but this really is a weekend vehicle and I just need it to last from Sunday to Friday night.

The battery is brand new as of 3 months ago (along with water pump, timing belt, serpentine belt, etc.) and the alternator checks out fine.

Is there anything that might be kicking in after 2 days that could be causing this? Potentially related to the radio or head unit? I do have Navi in mine and the only glitch that I experience is that the radio cuts out for a split second every few minutes. Barely noticeable but I am not sure what may cause that and if it is related. I have tried keeping the doors locked, turning off all lights, disabling the alarm. I bought a automatic battery kill switch but hoping there is something else I can try before resorting to this. Jumping with a portable jumper seems to work great if that helps. Thank you.

 

[Julian Stead]

Pull the fuse for the radio and give it a try, this and cd players are the most common cause, and as there is a fault with the radio then this is pointing you towards this.

 

[CurbsEnthusiasm]

While it won’t resolve the problem, I’d recommend a battery trickle charger / maintainer if your keeping the truck parked for a week+.

 

[MaineiacMoose]

I am with the OP. My Lexus does the same thing after 3-4 days it wont start the truck. I was chalking it up to the auto light sensor and an old battery but after shutting that off and charging the battery still a no go after a couple of days. Keep us informed OP hope it works out as something simple.

 

[primetime4]

Thanks for the replies.

I jumped the truck again tonight (those portable jumpers work great by the way) and pulled the radio fuse from the fuse box in the engine bay expecting to kill the radio. There seems to be no effect as the radio still works as normal. Anyone happen to know what this is for? A quick search did not return an exact answer but I left it out. I also pulled the CIGAR fuse that powers the cig lighter, audio, and aux power outlet. The problem this powers the entire center console which also kills climate controls. I might pull the control unit out and try to unhook just the radio manually but the controls are integrated with the NAVI screen so might not be possible. I thought about a solar powered trickle charger that someone recommended but I am determined to figure this thing out if I have to rebuild this thing part by part.

 

[bchan]

my 99 land cruiser also has parasitic draw on my battery when parked. it usually takes about a week of non operation before it dies. would like to know if anyone else has solved this problem!

 

[aging fleet]

Thought I remembered people getting large draws from the dome light circuit when DVD players were installed, if you have one, it may be worth checking.

 

[RND1]

Not an answer to your question, but I installed a priority start after chasing a parasitic battery drain. It auto detects battery voltage and disconnects the battery when it drops below 11.5 volts (or there abouts). If it's dead after a few days, simply press on the brake pedal and the battery is reconnected and you're off.

https://www.amazon.com/PriorityStar...qid=1512010086&sr=1-1&keywords=priority+start

 

[primetime4]

Not an answer to your question, but I installed a priority start after chasing a parasitic battery drain. It auto detects battery voltage and disconnects the battery when it drops below 11.5 volts (or there abouts). If it's dead after a few days, simply press on the brake pedal and the battery is reconnected and you're off.

https://www.amazon.com/PriorityStar...qid=1512010086&sr=1-1&keywords=priority+start

I bought one of these as well (the HD version) and am prepared to install if I cannot track this down. I am worried that cutting off battery power to the ECU may affect performance but that would be better than killing the battery every week. But if these work reliably I might just give up and install the thing. I've been trouble shooting this thing for weeks now and am starting to think the truck is thinking on its own.

 

[ranma21]

Check alternator. Could be a bad diode.

 

[RND1]

Have you put a meter on your battery and pulled fuses to see which fuse removes the current drain? For me it was the BAT fuse, which is common (search for parasitic drain BAT fuse here). Problem is the BAT fuse goes to a circuit that covers the radio, dome light, CD player, amp, nav, etc.

 

[primetime4]

The 2 dealers that I took this to put a meter on it and could not find anything. One tried it for a week I am guessing they turned on or off something daily that might have prevented the cycle from starting. The second dealer had it for a day and returned it saying everything was fine. 3 days later, battery is dead which is why I think it might be a delayed drain like something is turning itself on after the first 1-2 days if left untouched. Both supposedly checked the alternator as well.

I cannot find the BAT fuse in any diagrams. Do you happen to know if it is behind the kick panel? I pulled the CIGAR fuse which is supposed to control audio, cig lighter and power output on the center stack.

 

[RND1]

I cannot find the BAT fuse in any diagrams. Do you happen to know if it is behind the kick panel? I pulled the CIGAR fuse which is supposed to control audio, cig lighter and power output on the center stack.

It's in the fuse block in the engine bay behind the battery.

 

[primetime4]

It's in the fuse block in the engine bay behind the battery.

I am looking through the manual and do not see anything labeled as "BAT" or "BATT". But I did read that the ECU-B fuse can be a culprit. This controls: Power tilt and telescopic steering system, daytime running light system, theft deterrent system. I will pull this tomorrow and see what happens.

 

[RND1]

This is the thread with lots of info on the BAT fuse:

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

 

[Trollhole]

Most wont sit in the car long enough for it to go into sleep mode. Or won't disable a door switch. I believe it takes about 15 min for it to go into sleep mode. We disable both front doors. Put an amp meter on the ground side of the battery and wait. Usually after 15 min it will go in sleep mode. Then we just wait and check the meter throughout the day. I've even stuck a camera to the meter to notify me when it changed at night. Usually the problem is just after when it should be sleeping. It was the ECU memory fuse that was the culprit. Once it was in sleep mode and we see the drain we start pulling fuses. The customer with the ECU drain had a choice. Replace the ecu or live with it not having memory and resetting every time the key was turned off. They decided to just leave the fuse out. A year later no issues. Other than a high idle at startup.

 

[medtro]

Could be the audio amplifier under the passenger seat. I have seen one with a switch installed under the seat to turned off the amplifier in order to avoid the draining problem.

 

[primetime4]

I have been through the "BAT Fuse" thread a few times and still cannot determine exactly what this is. There is nothing labeled as "BAT" so it sounds like it might be a combination of ECU and DOME fuses? I am planning to pull the ECU-B fuse to see what happens.

Regarding the ECU memory fuse, do you happen to remember which fuse that one is? I am tempted to make the trek down to SC to have you look at my LC. It sounds like you guys really know how to check for this unlike my local dealers. Thanks.

 

[aging fleet]

Link to Electric Wiring Diagram (EWD) provided by @2001LC, you're probably going to need it if you don't already have it.

UZJ100 Electric Wiring Diagram (EWD) down load

 

[Julian Stead]

Link to Electric Wiring Diagram (EWD) provided by @2001LC, you're probably going to need it if you don't already have it.

UZJ100 Electric Wiring Diagram (EWD) down load

This is for the later landcruiser where they added multiplexing. If the radio doesn't switch off after pulling the fuse then maybe someone has been altering the electrics, pull the radio out and see if there is anything obvious, then leave the radio disconnected. Maybe someone has fitted a aftermarket amp.