well all started with the second set down led on each brake lights on all the time,so started with changing the FSR and the brake light switch,and its still the same so continued with a few bits as seen on other topics about battery drains,also had the LCM repaired,removed the pin 7 on the ABS ECU and also removed every fuse from all the fuse boxes but the drain is still there 8 volts, the brake lights work as they should but every time the leds come on dim and get brighter,i have checked for water in all the places and cleaned out the sunroof drains i am now loosing the will to live if anybody could point me in the right direction or has had a fault like it any help would be received ps the alternator and battery have been checked and are both good

on the mercs the reg pack on the alternator can fail and cause such a fault

I think alternator as you say as with all the fuses removed there can't be much left connected unless there is a short to ground somewhere or the battery is in fact failing.
You could check the wiring by the battery as that can become worn.

You are getting 14.6 volts approximately with the engine running?

Headlight wipers failing to park on these cause battery drain but without fuses I can't see it happening but you could disconnect them at the multiplug behind the head light or up behind the bumper, I think they are a black and white large plug from memory.

Did it start suddenly and are your brake lights or any other lights after market LED ones , I had a set of LED number plate bulbs which nearly caught fire and threw loads of LCM module faults ?
Anything on diagnostics ?
You can try and measure current drain across the battery but without any fuses I'm not sure what else could be connected other than the internals of the alternator or a short as already mentioned above, if you can unplug the alternator it might tell you something and I have a TD6 on my drive at the moment and that decided to try and set fire to the front engine electric fan for no reason, doesn't turn just smokes so I have disconnected the multiplug by the top left side of the radiator

Headlight levelling ECU if you have one can fail, it was removed from 04 onwards , its in the passenger footwell
Sorry bit of scattergun advice there

bembo449 wrote:

on the mercs the reg pack on the alternator can fail and cause such a fault

holidaychicken it started gradually I had a bigger battery put on last year the guy who checked the alternator said I was getting 14 volts which he said it was enough now you’ve said 14.6 that’s got me thinking ,I will give them all a good looking at cheers all ideas are Appreciated hopefully I can get it sorted 👍👍

I would expect to see more than 14 v but have a read of the following discussion, i may be leading down the wrong path ..

http://www.fullfatrr.com/forum/topic34018.html

If you measure the voltage across the battery when you park it up , has it dropped off significantly when you go back to it a day later ?

Yeah it has dropped a lot just checked the headlight wipers and the alternator unplugged and they are still on have to take a look at the power cables going into the car see if I can see anything

How are you testing this drain?


For a start you need to make sure the car is asleep.

Close all the doors apart from boot, passenger door and bonnet.
Then use your fingers to close the locks on the boot and the passenger door, and put something heavy on the bonnet catch (or you might be able to disconnect it).


While the car is going to sleep I would undo the big red cable on the bulk head, the jump point, and test the drain on that. That will tell you if the alternator is drawing current when it shouldn't be.

Then undo the battery negative and put the meter across that cable and the negative on the battery and watch its reading.
After 6 or so minutes it should drop from 6-8amp drawer down to around 1-2 amps, then after roughly 22 minutes it should drop again, ideally down to around 0.050amps or less.


If it is not dropping that low start to pull fuses, this is why you leave the passenger door and boot open, so you can pull the fuses.
Pull them one at a time and check the multimeter, if nothing changes put it back in and move onto the next one.

Idea to rest the multimeter against the windscreen so you can see it while you pull the fuses.

You can start to take reading before the car goes to sleep, but you need to wait the 22 minutes before you really know.

I would just wait and watch it and see what it reads as it drops, the chase the drain.

You will find it. Porsche 911 (996)
2015 BMW 5 Series Touring
Not got a LR of any kind at the mo, and got itchy feet.

^+1 But before doing that I would be inclined to charge the battery fully, disconnect the earth connection and leave it all night.
Check the battery voltage before leaving it overnight and again in the morning before you reconnect it.
Even new batteries can develop a fault very quickly.

can he not use a clamp meter ? that what I did when my merc had a battery drain , found the culprit in about half an hour

Yeah I guess so, but often clamp meters have a very short range and tend to cost 10x what a multimeter costs.

My multimeter was bought from a local store for £5.99 and works perfectly, very accurate down to 0.001 ohm.

My clamp meter was a cheap one at £40 and often reads differently every time you attach it! I'm sure it is juts a crap one though. Porsche 911 (996)
2015 BMW 5 Series Touring
Not got a LR of any kind at the mo, and got itchy feet.

This might be out of date advice but I’ll chuck it in as I know how it feels chasing this fault. I had a P38 that developed a drain problem, turned out to be the ecu waking up. The cure was a new radio antenae receiver unit which I assume had a narrower frequency band when listening for the key unlock signal. Apparently the old one kept hearing signals not from a key and kept waking when it shouldn’t have. It seemed, five years ago now, to be coincident with the rise in broadband wifi although I never checked frequencies to prove it was that. An indy LR garage changed the unit, never had it happen again in the three years I owned it.

I’ve got a multimeter to do the testing but I won’t get time to look Until the weekend now so give me plenty of time to make sure it’s fully charged and hopefully with all the advise I will find it and get it sortedthen all I have to do is sort the rear quarters out and archers

Have you found your problem? If not look at http://www.rangerovers.net/repairdetails/electrical/batdrain.html
This is the article I found when I had trouble with a P38. Spoke to my Landy Indy who knew the problem and said this was the know fix. It worked.
I bought an L322 on Saturday - hurrah! On Sinday it wouldn’t start! PO has fitted a battery isolator so it clearly has a problem. The radio receiver is going to be my first attempt at curing it.

Great info here. I have a similar issue with drain down. FSR was changed out last year. I know that is a common issue. I had the door opened for 3 days with the door card off for repair. Went to get some tool out of lift gate but no unlock. Yep all dead. Battery at 5.6v. Well I needed to disconnect the airbag anyway.

1. Besides the FSR and possibly the RF receiver being activated from rogue signals are there other common points of drain for the BMW years?

2. according to RAVE the RF receiver is fed directly from battery thought fuse 14. I'd assume pulling this fuse would sort out this as a problem. The link article implies it could still be fed current.

Here are my iidtool fault list. I understand the side mirror, drivers door lock, steering column motors(disconnected or removed), thermostat faults(thermostat mod done). Air quality sensor probably worn out. EBV function fault and random code tolerances I understand to be common and ignored. That leaves the headlight and light control faults unaccounted for and wonder what to do with them. Lights work great as far as I can tell.


ATC-Heat / Cool

• 0x30 Air quality sensor line fault


BPM-Body Processor v4

• 0x59 Driver door central locking mechanism broken

• 0xA7 Passenger door mirror horizontal potentiometer: defective


DSM-Driver Seat

• 0x11 Steering column radial motor - transmission error


ECM-Engine (ME7.2)

• 0x48C Electric thermostat circuit fault

• 0x48B Stuck thermostat fault


HID-Left Headlight

• 0x2A Ignition voltage < 7.5 volts


HID-Right Headlight

• 0x2A Ignition voltage < 7.5 volts


IP-Instrument Pack

• 0xBD EBV function fault received from ABS ECU


LCM-Light Control v11

• 0xC ECU EEPROM fault

• 0x0094 Unknown

• 0x0095 Unknown


PATS-AntiTheft

• 0x3 Key 0 - Random code tolerance increased