I've been away, but now i'm back... with a flat battery

trickyb · Post by **trickyb** » Mon 13 Oct, 2008 09:19

Hello all.

It's a while since i visited the site, or bumped into any of you's guys.

Been a bit busy with a change of job (within my job for those who know) and an addition to the family. Not a baby - don't be daft - but a dog who needed about as much attention as a baby. And don't get me started on the costs.

A few things appear to have changed around here. THE STICKERS!!!! Last thing i knew it was a sore point with endless posts discussing/arguing the issue. Glad to see that's been sorted and i'll be ordering my sticker off Giles asap.

Spunky - thought you and the wife were off to NZ??

Rob - see you're still busy with the calender. Great. no new pics from me this year, as yet, but i'll be sure to order one.

Anyway, to the sharp end. Started having battery issues a few weeks ago - just as the mornings were completely dark and the evenings are closing in. joy.

I checked the battery which had probably been in for 4 years and changed it for a spanking new one. I noticed a large amount of oxidized build up on the negative side and that one of the nuts on the negative clamp was missing - so does anyone have the size/pitch/diagram for that nut (larger one of the 2).

It was all hunky-dory for a couple of weeks until this morning. Flat again.

I'm going to do the multimeter check tonight and look for drain. I've noticed the boot light seems to work intermitantly, flickering on and off as you open the boot fully - sus to me. I seem to remember the switch being inside the boot trim near the lock? (Rob?) At the moment, i suspect this or the bonnet alarm switch - however the alarm hasn't been going off as other posters have commented.

I'll keep you informed.

Tricky

SpunkyM · Post by **SpunkyM** » Mon 13 Oct, 2008 15:18

Hello Rich, you're right has been a while - nice to hear from you again. We did go to NZ for 3 months but just for a holiday to check a few things out. Unfortunately just around the time we were planning to move out there NZ was hit by a huge house price bubble (much faster than in the UK at the time) and to make matters worse the NZ dollar went very strong against Sterling. All added up to costing about 60% more than it would have done the previous year. Kind of removed one of the major incentives for going out there (to be mortgage free) so it has all been put on hold while things stabilise.

Anyway, the boot light sounds like it could well be your problem - it's a common culprit for discharging batteries. Easy way to check is to see if the lens is warm after the boot has been closed for a few mins.

trickyb · Post by **trickyb** » Mon 13 Oct, 2008 15:31

Hi spunky.

WEll, you just wouldn't believe it, but a circuit somewhere is drawing 4.5 Adc !!!!

constantly.

I've had the multimeter on it and took out all 46 fuses one at a time with no effect whatsoever. I took the boot lamp out this morning

Bugger.

Are there any other fuses hidden away in the car that i've missed and/or a circuit which could be drawing such a rediculous current.

Keep thinking about a short somewhere but i'd still expect some sort of indication

help

trickyb · Post by **trickyb** » Mon 13 Oct, 2008 15:48

OK, done a bit more digging on t'internet.

Need to find the auxiliary fuse box and e-box (?) for fuses 48 - 205

Where the hell is that?

trickyb · Post by **trickyb** » Mon 13 Oct, 2008 19:44

Please ignore most of what i wrote above. Gibberish, at best

My battery has a 220mA drain at rest. Compared with Spunky's suggestion of 130mA ish, and Mike's suggestion (in another post) for 0.0xmA, it's a little high

I re-did the multimeter and fuse check and thought i'd isolated fuse 31 as the culprit. 10 times i removed that fuse to see 0.08 (80mA) - 0.10 (100mA) on the meter - much better, then replaced the fuse for it to return to around 220mA. bingo, thought I.

And, what do you know - the alarm's on that circuit. Bonnet switch was taking large bets, so i unplugged it - making no difference whatsoever!

Then, upon checking for the 15th time, the meter read 0.08A with the fuse in - Oh no, an intermittant fault.

And that's where i am now. I wobbled a few cables, set/unset the alarm and each time the reading was good and steady at 0.08A

Let's see what morning brings.

BTW, never sis find the auxiliary fuse box, only three relays to the right side behind the plastic panels under the sterring wheel

aj2007 · Post by **aj2007** » Mon 13 Oct, 2008 20:34

I believe the aux fuse box is indeed inside the car it only carries fuse 48 (40 Amp). The picture shows it below the steering wheel but this is on a left hand drive car Doh!

Have a look at the wiring diagrams for yourself see if you can work it out and the E box is under the bonnet far left:

http://www.gbnetwork.co.uk/bmw/downloadetm.html

Pages: 7100.0-08 - E -Box; 7100.0-20 Aux Fuse Box; 0670.2-03 Aux Fuse

Can you isolate the alarm siren? Could be knackered backup battery?

Regards

Ade

Post by **Robert T** » Mon 13 Oct, 2008 22:16

Hi Tricky, and welcome back. You were sadly missed at Tatton this year.

I am indeed on with another calendar for next year, which I'm having to squeeze in with a lot of travelling for work - not much time for zedding (or indeed frogging) lately.

The boot light switch is part of the boot lock. The little cone shaped bit on the latch depresses a microswitch in the lock part.

Not sure I can help with the current drain issue. 200mA would take 350 hours (14 days) to drain an average full charged 70Ah car battery. I would have hoped a short would cause a blown fuse rather than a prolonged current drain, so must be something else.

AJ's suggestion of backup battery might have some legs - you won't have a backup battery on the alarm siren on your facelift zed - but there may well be some kind of battery or capacitor on some of the other circuitry and these can fail in odd ways over time.

Hope you get it sorted soon.

Cheers R.

trickyb · Post by **trickyb** » Tue 14 Oct, 2008 07:05

Got to work this morning and re-checked my findings from yesterday evening.

Again 240mA (or so) being drawn from the battery. Removed fuse 31 and it dropped to 0.0xmA levels.

I've downloaded the z3 wiring diagram and identified the following circuits taking supply from that fuse, however i suspect not all of these are fitted to my 2.0 (W) z3 model

1/ OBD II Connector
2/ Electronic ~Immobiliser control unit
3/ Clock
4/ Antitheft LED
5/ Instrumentation
6/ On board computer (trip meter only for me)
7/ Gradient monitor
8/ Gong - (lights reminder, i presume?)
9/ Alarm siren
10/ Control unit - thermal oil level sensor

...could it be any more complicated.

To start with, has anyone removed/disconnected the alarm module on their z3? Where is it? Under bonnet or behind internal trim?

Just not setting the alarm won't work as this drain is happening all the time, not just when the alarm's set.

Has anyone else had any problems with these other items? And what were the symptoms?

Thanks again

Trickyb

p.s. Hi again Rob. Really sorry about Tatton. It's been manic for a year or so, but we'll be fine for '09. Talk soon.

Guest · Post by **Guest** » Tue 14 Oct, 2008 08:17

You should be looking at a 30 mA drain for a standard Z3 - looks like a problem somewhere.

trickyb · Post by **trickyb** » Tue 14 Oct, 2008 08:35

Hello again Mike.

I'm going to start by disconnecting the Alarm module completely and rechecking my results. Can you confirm whether it it is behind the glove box or under the steering wheel in a right hand drive car?

The wiring diagram i downloaded (allegedly for a r/h drive car) says it's behind the glove box - but is showing a picture of a l/h drive z3! Confusing or what.

I'll do the trim under the wheel first, if no-one knows, as that's far easier than taking the glove box out.

trickyb

Guest · Post by **Guest** » Tue 14 Oct, 2008 09:42

I have been behind the instruments in my car, and there are no modules hidden there. Look behind the glove box, where most of them live.

You will just have to disconnect the services from fuse 31 one at a time.

I would try disconnecting the instrument cluster plugs first, as it may be that the batteries on the Service Interval board are dying of old age, or have been damaged by being flatenned and then charged mightily by a recharged main battery being connected.

While you have the instruments disconnected, check that the wires have not been damaged by chafing on the curved steel bracket behind you will see behind the cluster. This is a well-known cause of various problems.

Being NiCd types, they need a restricted initial charging current until they are about 505 charged - a fully charged main battery will just charge at full current, and after a couple of time the NiCd batteries begin to die, and take a higher than usual charging current.

Another good 'possible' is the oil level sensor on the bottom of the sump, which has a small heater in it. They are known for failing, and it would be easy to unplug it.

You can't beat leaving the car connected to an automatic charger all the time, particularly if you are not going to use it for a while.

Good luck!

Justin Time · Post by **Justin Time** » Tue 14 Oct, 2008 12:04

Why not try removing one of the terminals from the battery, connecting it to a multimeter, and then connect the other multimeter electrode to the battery, bridging the gap. Turn on then off, all the electrics in the car by the ignition, then wait a few minutes for the car to totally switch off. In those minutes of waiting for a full shut down, you should see a few amps being used. After everything shuts down, there should be below an amp of drain, if any.

If there's more than an amp of drain, with the multimeter in place still, try removing (one by one) the fuses and relays to identify the problem circuit.

SpunkyM · Post by **SpunkyM** » Tue 14 Oct, 2008 12:26

I think that is pretty much what he has been doing Justin.

Rich - the trouble with the alarms on these cars is that they were not fitted by BMW so they are not all in the same place. But I think the alarm has to be the first thing to eliminate now you know it's not the boot light. They are notorius for this sort of thing. I bet it is that.

Guest · Post by **Guest** » Tue 14 Oct, 2008 13:07

Justin's comments jogged my memory - does the 240 mA remain constant, after say 30 seconds? The OEM alarm, for example, reduces its current demand after it has carried out its self-test routine and is fully armed.

Justin Time · Post by **Justin Time** » Tue 14 Oct, 2008 13:58

SpunkyM wrote:I think that is pretty much what he has been doing Justin.

I completely missed this:

trickyb wrote:I'm going to do the multimeter check tonight

Oops.

henrycrun · Post by **henrycrun** » Tue 14 Oct, 2008 14:19

FWIW (and its not worth much!) the Haynes American softback "3 Series 1992-1998 (also includes Z3 models)" manual
shows a photo (claimed to be a Z3) showing a 40A fuse inside the car "located above the left kick panel"

aj2007 · Post by **aj2007** » Tue 14 Oct, 2008 16:24

Don't forget the gradient alarm (Tilt Sensor) is part of the alarm system along with the siren fed off fuse 31. I believe this is mounted in the boot L/H side behind trim. Try the easy things to disconnect first

Post by **Robert T** » Tue 14 Oct, 2008 18:24

Justin Time wrote:I completely missed this:
trickyb wrote:I'm going to do the multimeter check tonight

How on earth did you think he had been measuring the current? Sticking his tongue across the terminals.

There is some merit in leaving the car for a period of time with the doors, boot and bonnet all closed. Tricky's alarm is like mine, so when the car is unlocked, it should be unset, but on arming, the LED flashes for about 30 sec before the interior sensors are activated - as Mike says, the current should settle after this has happened. I am not sure what current the alarm will draw with the alarm unset.

On a similar vein - if you have had the ignition on, you may have started the fan on the ECU - so you need to leave time for everything to go into "standby" mode before trying to get a current reading. Might this account for the current drain?

If you have disconnected the bonnet switch, then you should at least be able to work under the bonnet without affecting things adversely.

Cheers R.

trickyb · Post by **trickyb** » Mon 20 Oct, 2008 08:55

Thanks for all the replies, guys.

Some increasingly strange results following continued fault finding on Friday (1st day it'd been dry all week), but still seem to be pointing the error at Fuse 31 circuit.

However, to quickly answer the previous posts - i had been waiting for a good couple of minutes following the locking of the car to hope for the current to settle down, but it always remained pretty constant around 240mA. Removal of said fuse drops the drain to around 80mA

I've disconnected the bonnet and gradient monitor. No change.

Stripped the inside of the car out and got access to all the components under the steering wheel and behind the glove box. I disconnected every single one, and yet the current remained stuck on 240mA !!

Couldn't believe it.

unfortunately, not all the components had clear description of their function on them, so i'm not exactly sure what's under there. I did however identify the Alarm console, and know i've now disconnected this with no improvement in current drain.

...The saga continues. As mentioned earlier by Mike, the dashboard may have to come out next...

Trickyb

henrycrun · Post by **henrycrun** » Mon 20 Oct, 2008 14:08

Not a permanent solution, but you could leave a 12v solar charger connected to the cigar lighter for now.
Something like this http://www.maplin.co.uk/Module.aspx?ModuleNo=98358

jollyassassin · Post by **jollyassassin** » Mon 20 Oct, 2008 14:34

Thats a good idea for anyone who leaves the car standing for a few weeks.

Guest · Post by **Guest** » Mon 20 Oct, 2008 14:57

Try disconnecting the alternator, which may have a duff diode.

Also, disconnect the main battery positive cable, so isolating the starter motor, and then use the meter to connect the battery positive terminal to the small red wire only. This will show if the source of the drain is in the sarter motor or therest of the electrics.

If yu have elecricity in your garage, forget about solar chargers - they are gutless and expensive. Buy a £25 Gunsons automatic charger frmo German & Swedish.

estocks · Post by **estocks** » Mon 20 Oct, 2008 18:48

Is the current drain different if you don't set the alarm?

trickyb · Post by **trickyb** » Mon 20 Oct, 2008 21:02

Thanks for the replies/ideas today gents.

Will post again once those checks have been carried out - when it stops raining.

RB

henrycrun · Post by **henrycrun** » Tue 04 Nov, 2008 21:48

TB, any updates on the current drain ?

trickyb · Post by **trickyb** » Wed 27 May, 2009 10:37

UPDATE and RESULT.

A couple of weeks ago my central locking just stopped working.

As i'd already identified this was covered by the suspect circuit, it had to be connected, however i wasn't in the position to investigate myself so into BMTEC in Manchester it went. (service was due anyway)

Turns out the fault was in the loom to the boot - the one visible on the left when open.

The engineer at BMTEC said that several of the cable's insulation were perished and exposed areas touching causing both the central locking issue and current drain.

VOILA. Fixed. Left the car for a week - started first time as it should.

Thanks for all the earlier posts.

Post by **Robert T** » Wed 27 May, 2009 18:11

Good to hear from you Tricky and glad the car is sorted now.

Do you fancy coming along to Tatton in September again this year?

Cheers R.

zroadster.net

I've been away, but now i'm back... with a flat battery

I've been away, but now i'm back... with a flat battery

Drain

Modules

Justin

Drain