Electrical problem - any thoughts?

Herbie · November 28, 2022

1 hour ago, Scribe said:

Meanwhile I thought I was doing the right thing by going to a Lexus specialist, but maybe I shouldn't bother. As you say, it's just a car.

Exactly.

I'd probably go to a Lexus or a hybrid specialist for something like the hybrid system but for things like this, no. A car is a car, is a car in this context. They all have brakes, they all have cooling systems, they all have engines and so on.

Supafly · November 28, 2022

On 10/14/2022 at 5:02 PM, Herbie said:

If you don't want to tackle it yourself, you don't say which part of Sussex you're in but here's a couple of places with good reviews:

https://www.autoelectrical-crawley.co.uk/car-electrician-sussex.html

https://www.stevesautolancing.co.uk/

https://www.autoelectricdiagnostics.co.uk/services

https://www.tmeautoelectrical.co.uk/

I've also found these folks: Scantec Automotive | Diagnostics | East Sussex (scantec-automotive.co.uk)

If they can resolve BMW electrics then an older lexus should be easy for them 🙂

Malc1 · November 29, 2022

15 hours ago, Supafly said:

should be easy for them

all fingers, somehow crossed eh !

Malc

ROYT · November 29, 2022

If the Battery is draining ,parasitic draw as previously suggested, also check the glove compartment light goes off, vanity mirror lights and any footwell courtesy lights etc along with boot light you have tested already. You say all goes dead, if it won't crank and you know the Battery is fully charged and everything is completely dead you are back to the main thick Battery cables. There must be a break in the wire somewhere or a bad earth connection.

Scribe · November 30, 2022

It's as if there are two problems - poor connection and Battery drain. The first seemed to be fixed, the second obviously isn't. I'm wondering if they're linked or whether it's a coincidence.

ROYT · November 30, 2022

How are you re- charging the Battery?

Are you convinced the Battery really is fully charged. Once you are driving the alternator should maintain the Battery, unless you are doing very short journeys and it doesn't get time to replace the starting drain. After leaving the car overnight does it crank over 'briskly' or poorly? If it's dead flat and you are sure it's not a faulty Battery ,borrow one and if that goes flat you know it's a parasitic drain.

Scribe · December 1, 2022

I put the charger on at 8.00 yesterday morning, and seven hours later it showed 100%. This seems about right for a large Battery on normal (not trickle or jump-start) charge.

As soon as I switched the charger on I heard the CD autochanger whirring - this is the first sign under the bonnet that power has been reconnected. And when I opened a door the courtesy light came on. Before that, there was nothing. As the charge increased, more and more things started to work - the light round the ignition switch, the flashing security light etc.

The reason I don't think the battery's faulty is that (1) it's only about 2 years old, (2) my usual mechanic said it takes charge from the alternator as it should when the engine's running, and (3) it does charge up. From my experience, the engine should turn over before the battery's fully charged - say 70% - but when the charger shows 100% it cranks very briskly, so I'm assuming the Battery does charge fully.

Last time the car died, it was within three days of being used normally (not very short journeys). And it wasn't a case of the Battery being flat and getting clicks from the starter - there wasn't even an ignition light. My garage said the Battery must be completely drained, which in three days could only happen because of a parasitic drain.

I feel like I'm writing a book here, but maybe it'll help someone if they have the same experience. I should know more tomorrow.

ROYT · December 1, 2022

I don't quite follow your post, you say as soon as I ' switched the charger on', at that point do you mean 'switched the ignition on' If the charger is connected to the Battery it will supply power to the car for limited systems. The ignition should be off until you remove the charger, indeed I always take the key out if I have to charge the Battery, until the charger is removed. You say more and more things start to work, if the Battery is charged everything should be 'alive and come on straight away not one after another. Look at the fuses carefully, see if any look like they are running hot or are corroded.

Scribe · December 1, 2022

I meant I connect the charger to the Battery terminals before plugging it in. The ignition is off throughout the charging process.

ROYT · December 1, 2022

OK.

I still think it's the main Battery cables that are suspect, 1. bad earths as most people think. 2. Possible internal/ external corrosion of either lead, creating intermittent connection.

Worth a look for damp in the fuse box[s] but most of starting system is usually separate.

Let us know what the end result is!

Scribe · December 1, 2022

What you're suggesting is that the connection and draining problems are linked, not separate, which wouldn't surprise me. I suspect there aren't many coincidences when it comes to car electrics.

BigBoomer · December 1, 2022

Something is draining your Battery. You need to find out what that is before anything else.
If it takes 3 days to flatten the Battery whatever it is must be drawing a few amps.
Bad connections do not drain batteries unless they are short-circuiting the Battery and if that was happening you would probably have a smouldering wreck by now. :scared:

Also, if you fully discharge a Battery, it damages the Battery permanently. Lead Acid batteries do not like being fully discharged except for "deep discharge" ones that cost a LOT more than normal car batteries. Your Battery sounds like it's charging OK, but if there is no external parasitic drain then it may have an internal short of that is causing the discharge. Personally I would buy a new Battery and fit that. Then you can fully charge the old Battery and leave it in the back garden to see if it discharges itself. If it does, do not charge it again.

Herbie · December 1, 2022

Fully charge the Battery and then drive to almost anywhere that sells car batteries or any garage and ask them to do a load test on it. It'll only take a couple of minutes and most places will do it free and this will show up any bad cells.

I understand that you don't have a specialist auto electrician near you, but are you at least taking it to someone who hasn't seen it before? I ask because the things your usual place have tried up to now do not fill me with confidence that they know what they're doing. Remember that even if they do find a parasitic drain, then they have to start looking for what's causing it and fix that problem.

I don't know anything about you Andrew but I assume that carrying out the parasitic drain tests (as per videos earlier in this thread) is not within your skillset or you would have done it by now and told us the results, so make sure that whoever you take it to tomorrow knows how to do it.

Scribe · December 2, 2022

George, what you've said makes sense, and I'm going to get a new Battery in case the old one is damaged. If the current one is faulty I can get it replaced under warranty.

Herbie, you're right about my skillset (lack of), and I do sometimes worry that my usual garage is too busy to look at things properly. That was one reason for trying the new place, another was that one of the mechanics was Toyota/Lexus trained with the owner of my regular garage (who's looked after the car for the last 12 years). But the reason you're critical of them may be because I haven't explained the situation fully. To be fair to them, all I asked them to do last time was look at the terminal connections, which I thought was the problem. They did this while I waited, and it was basically a test to see if the connection would fail again, which it hasn't. I thought the problem was sorted, and had no idea the Battery was going to drain again.

The car has gone back there today, and this time they asked to have it all day so they can check the Battery and wiring, probably change the terminals permanently, look for drains etc. Surely it's fair to give them a chance to do this, which they didn't have last time? I certainly wouldn't go back to a garage that cocked things up, but that's not what happened. I have no reason to think they can't trace a drain and fix it, given time, or at least no reason to think a different garage that I've never been to before will do any better. Apart from anything else, I work full-time and don't have the time to drive around trying new garages, especially out of area. But hopefully I'll know more later today.

BTW I checked the Battery yesterday evening and the charge had gone down to around 85% within 24 hours. I hadn't started the engine. I put it back on charge for a couple of hours, then the charger showed 100%. This morning it turned over normally and fired straight up, the VSC light went off after a few seconds, and all seemed normal - though we know it isn't!

Scribe · December 6, 2022

Well, the garage had the car all last Friday. What they found:

1) Although the battery's 20 months old and has been completely flattened a few times, it's in good shape and charges to 92%. No internal faults.

2) Alternator working as it should

3) Starter motor working as it should

4) They had an amp meter on the car all day and did find a drain, which was at 0.10 for the first three hours. This then dropped to 0.02, which they say is the normal rate, given that the various 'open' circuits on the car (security system, clock etc.) always use a small amount of juice.

The problem with the big drain, which completely flattened the Battery in three days, would be locating it, because it isn't constant and didn't happen at the garage. While it's happening you could presumably check by taking out fuses or measuring the current across them (?), but if there's no drain there's no way of knowing where it has happened, and might happen again. Since Friday I've been connecting the Battery charger every day to check the charge, and it hasn't gone below full, so no top-up needed yet. I last used the car two days ago. This suggests that the drain has stayed at 0.02, i.e. normal.

I eventually found an auto electrician reasonably close to home but they said they won't touch such an old car because they can't get a wiring diagram for it (my garage wondered why they would need this anyway when checking for a drain). The nearest Lexus main dealer is now a fair way away, and I'm wondering what even they can do if the drain is intermittent.

Meanwhile my garage has replaced the Battery terminals with genuine Toyota ones, to make disconnecting the Battery easier - I'm probably going to do this over the winter anyway when I'm not using the car much. Otherwise, all I can do is keep checking the Battery. If the drain was still there it would have half-flattened the Battery by now, so I'm wondering if the garage touching the electrics has stopped the problem, at least for a while. Malc, didn't you say you had a mysterious electrical problem that did the same?

steve2006 · December 6, 2022

The picture shows the 2 main earthing cables (Battery negative) on the LS400, there is another cable which is bolted to the passenger side inner wing just rear of the Battery.

Given the ongoing problems I would locate all these cables, unbolt them, check the ends into the terminals, clean up the connections, fixing bolts and mounting points then reassemble.

Malc1 · December 6, 2022

4 hours ago, Scribe said:

Malc, didn't you say you had a mysterious electrical problem that did the same?

Wot me . well not recently ....... I did have a weird electrical problem that manifested itself about 18 months back ( I think ) getting to a hospital appt, the wipers and all else electrical just " died " in the rain on the M2 ...... the RAC guy was called from the hospital car park to which I had limped, and literally about 2 mins before he arrived everything began to get back to normal and, touch wood, been all ok since ............

He investigated but couldn't find anything wrong and following that i tried to find a Professional Auto Electrician to search for the problem and advise ....... I don't believe there's one out there . they might all be complete charlatans to my mind ........

I'm happy to put my continuing ( fingers and all toes xd ) Trust in my Mk3 Ls400 of 1995 vintage 🥰

Malc

Herbie · December 7, 2022

On 12/6/2022 at 1:44 PM, Scribe said:

but they said they won't touch such an old car because they can't get a wiring diagram for it (my garage wondered why they would need this anyway when checking for a drain)

Because, as you'll see from the screenshot below, one fuse can cover many circuits. Once the drain can be narrowed down to any given fuse, you then need to look at each circuit downstream of that fuse to find which is causing the problem.

On 12/6/2022 at 1:44 PM, Scribe said:

4) They had an amp meter on the car all day and did find a drain, which was at 0.10 for the first three hours. This then dropped to 0.02, which they say is the normal rate, given that the various 'open' circuits on the car (security system, clock etc.) always use a small amount of juice.

I'm not convinced there's actually anything wrong with that draw of 100mA because you must allow time for the car to 'go to sleep' and it's not beyond the bounds of possibility that it could take that long to happen. You need to open the bonnet, doors and boot, then manually trip each lock into the 'Locked' position, which allows the car to go to sleep but still gives you access to the fuses to run tests (as demonstrated in the videos above).

On 12/6/2022 at 1:44 PM, Scribe said:

The problem with the big drain, which completely flattened the battery in three days, would be locating it, because it isn't constant and didn't happen at the garage. While it's happening you could presumably check by taking out fuses

Once the car is asleep you never remove fuses because that could 'wake up' one or more of the ECUs and if that did happen, any tests from that point onwards would give erroneous and false results.

Mikaelse · December 12, 2022

On 10/15/2022 at 1:47 PM, Herbie said:

One other thing has just plopped into my head re the negative lead. Battery clamps can be overtightened and if that happens the battery post itself can break its connection with the negative plate in the battery case, so make sure it's not the post itself causing the intermittent fault.

It really sound like there is something that is intermittnetly wrong INSIDE the Battery.
Everything stop working while driving and getting back to life after wiggling on Battery poles should be conclusive if Battery poles and connections looks fine.

A good Battery should solve it. I do recommend a good AGM Battery .
Lots of cold crank amps is good but I use a 70 Ah and that works fine even in COLD Sweden.
AGM batteries often charge back up 3 times faster than the standard type and keeps charge better.
My 1998 is LS400 is sensitive to weak batteries.

Scribe · January 20, 2023

Brief update: I've had no more problems with the car, and despite not being used during December it started up fine after a few weeks of cold weather. I checked the Battery first, and it appeared to have retained full charge since the previous journey. So it feels like it's fixed, and that the problem was the earthing. But I've got used to checking the charge before using the car. A good sign is that when I go in the garage I can see the red security light flashing on the dashboard - which means there's still some juice. I have a motorway trip coming up, which will give the Battery a good charge-up.