w245 battery dies every night.

[baber]

hi all.

got a bit of a pickle on my hands.
my mum's w245 b180 CDI k(2007)d the battery every night.

old battery was replaced as it was knackard.

parasitic draw test done. stayed in the car for over an hour, doors locked, watching the multimeter reading fluctuating between 6miliamps to 1.2amps.

I have only managed to pinpoint one fuse upto now with around 500miliamps draw intermittently, which is for the instrument cluster.

as the fluctuations don't last more than a few seconds I can't pinpoint any of the other fuses.


things I have done so far.
unplug the instrument cluster.ade no difference, although removing the fuse stops the 500milli amp draw, also ther are no other circuits that use fuse number 3 according to the fuse chart.

was told altenator could be faulty, so removed and tested again with no difference, (altenator diode tested, which shows its faulty but after speaking to a altenator specailist they say it can not be tested properly as its controlled by the ECU?)



just think it might be worth mentioning, when we bought the car, the cabin filter area was flooded with water. I cleared the drain plug and the blower motor works fine, and I have also disconnected this alswell just to rule that out.


also, I do have a scrap b180 sat in my garden to steal any parts off if needed.

could anyone give any advice or point me in any direction?


thanks, Baber.

 

[mersum1es]

Lot of stuff communicates via instrument cluster, so you probably isolate some of the drain there. However 500mA is still far too much. Have you gone through all fuses already? Intermittent behavior sound like some device in CAN is trying to do something. Reading fault codes sometimes helps to pinpoint culprit, and one isolation method is dig up CAN connectors and by unplugging them you can again isolate half (not sure how many BUS W245 has) of the devices.

 

[ajlsl600]

Lot of stuff communicates via instrument cluster, so you probably isolate some of the drain there. However 500mA is still far too much. Have you gone through all fuses already? Intermittent behavior sound like some device in CAN is trying to do something. Reading fault codes sometimes helps to pinpoint culprit, and one isolation method is dig up CAN connectors and by unplugging them you can again isolate half (not sure how many BUS W245 has) of the devices.

good luck to the op .. modern cars and in my experience benz electrics/electronics are a b/ minefield that even the dealers dont fully understand .

 

[umblecumbuz]

If battery dies overnight, how is it recharged next day if the alternator is kaput? From the way you worded your post, I assume you are using the car daily.

 

[Blobcat]

Hello and welcome

I think the water damage needs further investigation. I’d be looking for corroded terminals and anything that could have suffered from water ingress. Plays havoc with electronics and gives multiple random faults

 

[ZZZZ]

Hi and welcome!

Do you have a telephone pre-wire option in your W245?

Once flooded, the UHI control unit (under the passenger seat) will draw power and generally misbehave - better to remove and replace, if the function is actually needed.

Also, car of this age (mine is 06-reg) often had Nokia system fitted, and this one is a monster, both in terms of draining the battery and trying to find and remove all the bits:

I would also check the two main ground points in the front of the cabin - forward part of the door frame, about 4-6 inches from the floor each side - juts behind the round section of the trim. Water ingress can damage these, as already mentioned above. One other module to check: SAM (signal acquisition and actuation module) - below the glovebox, behind the trim (not my car, I just added cute arrows and text )

 

[baber]

Lot of stuff communicates via instrument cluster, so you probably isolate some of the drain there. However 500mA is still far too much. Have you gone through all fuses already? Intermittent behavior sound like some device in CAN is trying to do something. Reading fault codes sometimes helps to pinpoint culprit, and one isolation method is dig up CAN connectors and by unplugging them you can again isolate half (not sure how many BUS W245 has) of the devices.

i have, but after i remove the fuse for instrument cluster the other drain/s only come on for 1-2 sec then drop back down so i dont have enough time to go over the fuses.

If battery dies overnight, how is it recharged next day if the alternator is kaput? From the way you worded your post, I assume you are using the car daily.

the used to be used daily and wast just started nearly every morning but we have a spare e class to use at the moment although due to lockdown we dont really go out.
the diode on the altenator is like a 1way valve, if it beocmes faulty and lets current back through the opposite way, it would still charge the car when running but when off it could drain the battery. (that how i understood it anyway)

Hello and welcome

I think the water damage needs further investigation. I’d be looking for corroded terminals and anything that could have suffered from water ingress. Plays havoc with electronics and gives multiple random faults

i will look into this.

Hi and welcome!

Do you have a telephone pre-wire option in your W245?

Once flooded, the UHI control unit (under the passenger seat) will draw power and generally misbehave - better to remove and replace, if the function is actually needed.

Also, car of this age (mine is 06-reg) often had Nokia system fitted, and this one is a monster, both in terms of draining the battery and trying to find and remove all the bits:

I would also check the two main ground points in the front of the cabin - forward part of the door frame, about 4-6 inches from the floor each side - juts behind the round section of the trim. Water ingress can damage these, as already mentioned above. One other module to check: SAM (signal acquisition and actuation module) - below the glovebox, behind the trim (not my car, I just added cute arrows and text )

the car does have telephone pre wired into the armrest for the old nokia phone, i disconnected from the armrest but didnt really want to strip out the full interior, its never been used and would rather have it out, i will get moving and remove all the rest of the telephone setup. anyone need a free telephone kit?

ground points were checked and were all clean but will give them a once over when i strip out the interior.

will post back later with my findings and thanks all to those who replied.

 

[DREAMER NO2]

Can you remove the regulator from the alternator only 2 screws to remove it and check the length of the brushes .

 

[umblecumbuz]

Diodes rarely give trouble. They are solid state and - unless someone with far more electrical experience can come in here - do not change their characteristics even if wet.

 

[baber]

found that the Bluetooth module (I think) its fried. that's 1 thing done.

there was a bit of a puddle in the rear foot Wells. but all underside of all the carpets were soaking.


I belive this would have come from the heater blower intake so I'm currently stripping out the dash, then will take a look at all the electronics on the heater system.

will take a look at the altenator later on.

 

[baber]

I'm stuck on trying to remove the dash at the moment. its all loose and moves about but feels like there are some clips holding stopping it from coming out.

 

[DREAMER NO2]

Just get the blue tooth repaired first it might be the problem,, but i dont know . How can water get to the rear well if yiour serching under the dash .

 

[baber]

Just get the blue tooth repaired first it might be the problem,, but i dont know . How can water get to the rear well if yiour serching under the dash .

just going to leave the Bluetooth out. its never been used and never will be used.
not sure how water would get there and quite a lot of water, but I assume it's traveled through the heater blower all the way through to the rear foot well heaters and come out perhaps?

think I have found one power drain, the antenna Ariel module amplifier a1698200475. when I plug this in it causes a fluctuation in power draw upto 400m/a. can this part be swapped without any coding?

 

[ZZZZ]

Ah, great - now we're getting somewhere

1. The UHI - Universal Handy (German for "mobile phone") Interface - is not bluetooth-capable (hence no ID on the label) and is positively ancient.

However - one important thing to remember: as it's a part of MOST (fibre optic network), you must handle the orange wires with care (no kinks, no dirt on the ends), and you'll need to fit a fibre optic loop to close the err.. loop, otherwise the head unit and other bits won't work.

You can, of course retire the entire MOST network, which normally consist of UHI; head unit: Audio 20 or COMAND NTG2; CD changer; Bose amplifier (if fitted). I did just that and never looked back - let me know if you want details, etc.

2. The rear water ingress, is most likely coming from air pressure vents behind the rear bumper. I'm afraid, it's bumper out, air vents out, remove the cr@ppy rubber seals, tiger seal or similar, refit and breathe - been through that recently myself, also sealed the whole spare wheel well, for the good measure, as I have a factory subwoofer in the spare wheel - not something I want to test whilst submerged in water ...

3. The amplifier is not coded to the chassis, so can be removed and replaced, but you might not need to do that - now that the most likely culprit (UHI) is out, it could be fine. If you have a spare, then of course - it's very easy to do.

I'd still find that Nokia kit, if it's there - there were at least two power sources for this, including one off the back of the head unit ... sneaky bugger.

 

[ZZZZ]

These might be useful

 

[davemercedes]

Hello and welcome baber - glad to see you're getting good info and look forward to reading your "celebration" message soon.

 

[DREAMER NO2]

Glk is there any way you can get this bit of very good information put on to a sticky .

 

[ZZZZ]

Glk is there any way you can get this bit of very good information put on to a sticky .

Thanks
No idea, to be honest - I'm sure it could be copied, or I can upload again, if directed where to?

I actually found a couple of pics of W245 air vents water leak, and I'm pretty sure someone posted a more detailed write up recently on the same problem, with better pics, etc ...



As to the fibre optic loop - it could be either male or female, just need to check the socket on the gadget (UHI in this case) you want to by-pass.

Easily obtainable from eBay for a few quid:

https://www.ebay.co.uk/itm/UK-2-MOS...or-Audi-BMW-MERCEDES-MALE-FEMALE/174109369310

 

[Blobcat]

Thanks
No idea, to be honest - I'm sure it could be copied, or I can upload again, if directed where to?

I actually found a couple of pics of W245 air vents water leak, and I'm pretty sure someone posted a more detailed write up recently on the same problem, with better pics, etc ...

View attachment 56898 View attachment 56899

As to the fibre optic loop - it could be either male or female, just need to check the socket on the gadget (UHI in this case) you want to by-pass.

Easily obtainable from eBay for a few quid:

https://www.ebay.co.uk/itm/UK-2-MOS...or-Audi-BMW-MERCEDES-MALE-FEMALE/174109369310

@Uncle Benz posted the info on the air vent water leaks. There should be a copy in the DIY section

 

[baber]

hurray. i found the power drain source, i think.

so after removing the entire dashboard and disconnecting all the components/modules i was still getting fluctuating readings, just a lot less amps.

so connected all the components/modules back and pulled all the fuses out at once (i took a photo of them first)

put each fuse back in 1 by 1. if the fuse showed any power drawn i took it back out, so only the fuses that had no power draw were back in.

then 1 by 1 put each fuse in and left for about 30 mins to check that its has turned off.

down to my last 2 fuses that would not settle - SAM unit.


and then my back went.


now is the sam unit repairable? (i cant really move around alot right now)

or would i be better off replacing it? (can i buy a used one)

and im assuming it would need coding?


with regards to the water leak, ill ge3t that job done once i have this sorted, and the stereo still works fine with the UHI disconnected.