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Reverse charged battery and a CL500 - not a good combination!

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by fast28, Oct 2, 2013.

  1. fast28

    fast28 Senior Member

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    Location:
    Glos
    Your Mercedes:
    SL55-conversion (R129) & CL63 AMG (W216)
    Some weeks ago I had the mishap of one of every car owner's worst nightmares - attaching a reverse charged battery in a car stacked with sensitive electronics:shock:. During August I went on holiday and asked my Father to give the car a run or two to ensure the battery did not go flat, it has a habit of going flat after about 10 days; it's an original MB battery so 13 years old. On my last day away I got a rather anxious call to tell me the alarm was going off and "how does one turn it off?" I instantly knew the battery had lost charge and almost inevitably the result was the alarm sounding. It was slightly unusual in the fact the car had been run twice with no reported problems so it appeared the battery was now hardly able to hold charge being left for more than 5 days or so or an electrical item had not switched off. My Father was unable to open the boot with the mechanical key as it requires a certain "knack" so the alarm continued until there was no charge remaining to power it.:shock:.

    Arriving home to a quiet "dead" car I disconnected the battery terminals and measured the voltage, it was just over 8V. I placed my smart charger on the battery and left it for 16 hours. The next day I connected up the freshly charged battery, noting a few sparks than normal when the negative terminal was connected. I walked to the open driver's door and immediately noticed wisps of smoke and a strong burning smell coming out of the central front vents and also the windscreen wipers were on even though they were switched off!:shock::shock::confused:. I quickly disconnected the battery and tried to understand what had happened.

    Checking the fuses for the faulty circuit I found that more than one fuse had blown; Comand and navigation system, ignition coils, linguatronic ABC and windshield washer system, all three fuse boxes had blown fuses!

    Obviously something serious had happened, the battery appeared to have lost all its charge as nothing was working. Taking the battery out of the car and placing on a bench I hooked the charger up again, immediately the fuse on the charger blew, replaced fuse, it blew again, mmm:confused: tok a voltage reading with a multimeter: -3V :shock: placed the meter leads on the opposite terminals, positive on negative terminal: 3V! The battery had reverse polarity, how, I do not know, the times I've charged car batteries; I've never reverse-charged a battery and besides my smart charger surely would have blown its fuse?? I ordered a new battery online and thought I would discharge the existing battery by connecting a headlight bulb across the terminals and try to charge it again. After discharging the battery as much as possible still showing a small negative voltage I attached the battery charger again, it didn't blow the fuse so I left it to charge. The next day I found the charger had blown it's fuse again so gave up on it.

    With a fresh new battery connected up to the car I anxiously observed the interior for signs of smoke - none, and the reassuring sound of the soft-close windows operating could be heard:). But not all was right, the drivers door electronics would not work with the ignition in position 2 and the window would not go up although the soft-close feature was working, it was working for the passenger side. The courtesy side and fog light feature only worked on one side and the ABS, ESP, BAS and distronic systems were offline even after synchronising the steering angle sensor. The car started and ran fine although the engine was a little uneven at idle and the interior lights pulsed with the engine. I ran the car to work and back a distance of 45 miles and also noticed the Comand would not wake-up on the CAN and had to be manually turned on and off, it also gave a battery warning so I switched it off and noted the problem as another issue to look into. The next day I took the car into work, it was a dark rainy morning and my lights had come on, after 5 miles or so I was met by a red battery warning and within 2 minutes everything started to shut down one by one:shock:, dash lights, exterior lights, engine power, PML steering assist, making it to a car park under very low power I knew all hope was lost of making it to work and the battery was obviously not charging! The next couple of hours involved the RAC, a loan of a get-me-home battery and the news that my alternator was probably kaput :(.

    With some web research I concluded that my alternator's voltage regulator or most likely rectifier had blown and a likely replacement was needed. On further deep research of the problem I found out that there were two more fuse locations - one under the driver's footwell and one in the boot behind the battery mounted above the wheel arch. WIS confirmed the locations and I began the arduous task of removing the footwell carpet which involved removing the sill trim, accelerator pedal, side panel and lower dash panel. Upon discovering the fusebox known as X4/10 and removing the cables that fed power from the alternator to the battery and elsewhere I opened up the unit...

    [​IMG]

    Testing the continuity of the fuses I found the "smoking gun", the "midi" 150 amp fuse was blown on the alternator to battery circuit. After ordering the fuse online from an Ebay seller and eventually fitting it I measured the voltage at the battery - 14.2V :D. Now the alternator was charging the battery and one problem was solved. As one problem went another was discovered, I had no a/c blower speed apart from full-on:confused:. Another day was spent taking the passenger side lower dash cover off to access the blower fan regulator. Sure enough the speed regulator had burnt out, this must have been the cause of the smoke coming out through the central vents! A new regulator was ordered and blower speed restored although now I have a one constant low speed at all settings:confused:

    More of an issue was the ABS fault light which seemed to have switched off the BAS, ESP and distronic (although it said "speedtronic"). This certainly wasn't going to be the usual brake switch fault; all brake lights were working. The steering alignment was good so I investigated the wheel speed/ABS sensors, the navigation system was picking up a speed signal and my dash was displaying the car's speed correctly. Interestingly disconnecting a front ABS sensor caused a white ABC warning to come on and the PML steering electric assist to switch off. Using a newly bought Launch Creader VII+ diagnostics reader which can read the four main systems - engine, ABS, Airbags and transmission I was able to read a recurring single fault code - C1011 - A7/3 Traction system hydraulic unit - open or short. After interrogating the ABS pump wiring and relay I found the pump was getting voltage so the only other voltage supply had to come from the ESP-PML-BAS control unit to the A7/3 ABS valves. Internet research revealed a few companies offering to rebuild Mercedes ESP modules and one known cause was C1011. A search of Ebay found a seller offering a used ESP-PML-BAS control unit from an S-class W220 but it had the same MB and Bosch part numbers as my existing unit. So tonight I fitted the unit and bingo! ABS light goes out and the associated ESP, BAS and speedtronic warnings :p. No fault codes stored.

    So now I have a healthy car back on the road. The cost of this electrical disaster? ...

    New battery - £80.
    New midi fuse - £1.50
    Bunch of blade fuses - £3
    New blower regulator - £28
    Used ESP-PML-BAS ECU - £70

    Was I lucky or unlucky in terms of the damage I don't know? but what I can't understand is how the polarity reversed on the battery, did I charge the battery the wrong way around, if so why didn't the fuse blow on the charger or did the battery have a failure???

    Still have to sort out the blower speed problem though...:rolleyes:
     
    m2287 likes this.
  2. SL55 Mark

    SL55 Mark Senior Member

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    Your Mercedes:
    2004 SL55 AMG
    Is there a chance your dad charged it wrong way round ? Well done for sorting it out, and thanks for posting. I dread to think what that lot would have cost if you had not been able to DIY it.
     
  3. OP
    fast28

    fast28 Senior Member

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    Location:
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    Your Mercedes:
    SL55-conversion (R129) & CL63 AMG (W216)
    No he couldn't open the boot to get to the battery plus he wouldn't know where I kept the charger. I was dreading the EIS had blown, it would have got expensive then...:eek:
     
  4. television

    television Always remembered RIP

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    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    You have done well, if the battery was poor or next to no charge then it may have been possible to put a reverse charge in.

    Re the blower, if you have fitted the new one and its not working then do check the output from the control unit, this puts out 0 to 7 volts as far as I can remember, you have 4 wires going to the reg pack

    1 to the fuse box and a live of 12v
    1 to ground
    1 to fan motor
    1 to the control unit, and this one must get the variable voltage from the control panel.
     
  5. OP
    fast28

    fast28 Senior Member

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    Glos
    Your Mercedes:
    SL55-conversion (R129) & CL63 AMG (W216)
    OK thanks, I will check the control unit output.
     
  6. DIYMAN

    DIYMAN Senior Member

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    Your Mercedes:
    E270cdi/53 plate/2.7l 5cyl.
    A lead acid battery will revert to a negative voltage if completely drained say by a persistent short circuit, an intelligent battery charger will sense a reverse polarity connection and turn the dc output off.
    The way to try and recover the flat battery is by connecting it in parallel with a charged battery and charger.
     
  7. Irresistance

    Irresistance Senior Member

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    Gdansk, Poland
    Your Mercedes:
    1988 W126 420SE, 2006 W209 200K & 1999 S210 320CDI
    What I fail to understand though - you drive a CL500, yet you have never replaced a 13 year old battery that costs a poky 80 quid, and put up with worrying about it being charged for months (years?) on end... why??
     
  8. OP
    fast28

    fast28 Senior Member

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    Your Mercedes:
    SL55-conversion (R129) & CL63 AMG (W216)
    Interesting to know.

    Never worried about it, that's why I never got around to replacing it sooner, never caused any real concern. Maybe once a year it would go flat because it was left undriven for 2 weeks. The car gets driven everyday for commuting and pleasure so the battery usually has plenty of charge.
     
  9. television

    television Always remembered RIP

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    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    One never knows with batteries as there is no fixed pattern, some fail or shall we say wear out after a few years where as others go on for near on ever.

    I changed my battery on my SL at 4 years old as there were problems, I took that battery off and it stood untouched from 2006 till 2012 when I needed one for my CL420. It was dead flat as one would expect, after a 20 hour charge on a 10 amp charger it started the car fine and it has been on there ever since, it holds up well going some 4 weeks with not being used.

    I will know by the starting if that battery is going to fail, and at the start of the first frost I will know, no sense in me buying another battery just because it is 11 years old.

    My V70R had a spell some years back where it got through 6 batteries in 2 years, and yes all faulty batteries.
     
  10. Code999

    Code999 New Registration

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    Your Mercedes:
    CL600/2001/5.8L V-12
    I appreciate this detailed posting of the resolution to the problem Fast28. I came across it while 'Googling' for a solution to my problem, which lead me to the forums with your post. I have moments of sheer stupidity and for whatever reason I put the battery in backward, hooked the negative cable to the positive post and forced the positive cable onto the negative post. I went thru all of the fuse locations I could access and found many blown fuses. I didn't know about the one above the battery until reading your post and the one under the floorboard I knew about and ordered a replacement fuse for, which I have. Can you tell me about accessing the 150amp Midi fuse. I don't see a problem removing the fuel peddle, since I had recently replaced it and found that to be relatively easy, but I am concerned about removing the trim and panels without breaking anything. Were there any special tools required? I know this post was a few years ago, but I hope you or someone that may know the answer to my question will respond.
     
  11. OP
    fast28

    fast28 Senior Member

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    Your Mercedes:
    SL55-conversion (R129) & CL63 AMG (W216)
    Hi Code999, it's quite simple to access the fuse box under the carpet sections. Pull the plastic door sill up, this might require a bit of brute strength as it has plastic tabs pushed into metal spring clips and move the seat as far back as it will go. You might have to remove the black plastic under dash panel and vertical door trim too to gain access to the edge of the carpet to pull it back. The floor section is designed to be removed once the plastic trim and gas pedal are moved out of the way. The only tools required are for the various metric nuts and bolts that hold the fuse box together. I think the fuse box is always in the right footwell. Good Luck!
     
  12. Christiaan Soerjo

    Christiaan Soerjo New Member

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    Your Mercedes:
    2001 CL500 -W215
    Dear Fast28!


    My name is Christiaan and I live in The Netherlands, a mile from the Jost Frost bridge, known for the Battle for Arnhem... (WWII, Operation Market Garden, September 1944)

    I sure hope you are still out there and still returning to this forum regularly...




    Mine's a 2001 - W215 - CL500, just like yours. During what must have been a mental blackout/shutdown I reverse connected a backup spare/second battery that I carry around in my car since a few weeks...


    Slow discharge of my new Bosch battery

    The reason for the second battery is that after leaving the car 3-4 days untouched, the voltage drops just below what is needed to start my car. Alternator supplies a steady 14,0 - 14,1 V (checked in the special Mercedes-menu, on my heater's display) and my battery's a brand new Bosch 90 Ah device.

    Anybody an educated hint regarding what's drawing a current and draining my battery???

    I first found a CD stuck between the in-cartridge position and the position in which it can be played. I thought I had found the culprit; the small CD-transportation electric motor being actuated constantly since neither end-position switch indicates 'CD in cartridge' or 'CD in playing position'... After sorting the CD-changer, the slow discharging of my battery still occurs...


    Reverse connected spare battery


    The symptoms were identical to what you described:

    - Wiper blades funtioning inceasantly
    - Bose sound system dead
    - Comand system dead
    - Starter motor disabled
    - Dashboard stayed black
    - All kinds of electronic stuff disabled


    After disconnecting the second reverse connected battery and charging the new in-car Bosch battery:

    - Starter motor back online
    - No spark
    - Some problems solved, some still there


    After sorting some 4-5 fuses in the standard fuse boxes and in the Bose amplifier:

    - Engine starts
    - Most electronic devices back online
    - Comand & Bose sound system back online
    - Alternator DOES NOT WORK; problem remedied after reading your post and replacing the 150 A MIDI fuse in the passenger's foot well (just pulled back the carpet, no disassembly of the plastic sill cover needed...)



    PROBLEMS I AM LEFT WITH:

    - ABS, BAS, ESP fault codes in central display
    - ABC fault code in central display (color = white, system works normally)
    - ABS fault bulb lights up in the right side section of my dash
    - Distronic fault code in central display
    - Braking lights ON constantly (without me touching the brake pedal)


    So I ordered a replacement used CPU module ABS-BAS-ESP-PML from Ebay. Installed it. Problems still there... :eek:(


    THREE QUESTIONS:


    1) You mention the fuse box located over the battery, behind the trunk carpet/cladding, but you did not mention replacing any fuses there. Should I go there and replace (a) fuse(s) to solve my remaining problems?

    2) Isn't it necessary to have the local Mercedes dealer reset the fault codes in my car? Or do they go away automatically after solving all problems / changing broken fuses / replacing the ABS-BAS-ESP-PML CPU?

    3) Any other tips?




    Sure hope you, or any body else here, can help me fix my car... Don't even wanna think about a Mercedes-invoice for several hours of searching and finding nothing and/or with a quote for several hundreds/thousands €'s worth to make me a happy -driving- bunny again...



    Regards, Christiaan
     
  13. OP
    fast28

    fast28 Senior Member

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    Your Mercedes:
    SL55-conversion (R129) & CL63 AMG (W216)
    Hello Christiaan, welcome to the forums :)

    To answer your questions..

    1. I checked all the fuse locations all over the car to make sure all the fuses were OK. I don't think I found any blown fuses in the trunk area.

    2. I detected the ABS-BAS-ESP-PML CPU was damaged by using a code reader, I used my Launch CRP129 code reader, it can read ABS fault codes as well as engine codes plus transmission and airbags, it told me there was no communication to the ECU. It is also worth opening up the original ECU to see if there is damage caused by the voltage reversal, when I opened my ECU several components were burnt out and damaged beyond repair. I used my fault code reader to clear all codes once the replacement ECU was plugged in.

    3. It looks like your ABS-BAS-ESP-PML CPU is faulty by the same problems that I had. Do the part numbers match on the original and used ECU? same car etc.? It will help a great deal if you can read and clear any fault codes stored. Having a good fault code reader that can read several systems besides the engine is essential with these cars if you plan to work on them yourself!
     
  14. Christiaan Soerjo

    Christiaan Soerjo New Member

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    Your Mercedes:
    2001 CL500 -W215
    Hello Fast28! :eek:)


    Thanks very much for replying sooooo fast... You still own your Big Coupe? :eek:)

    I enjoy mine thoroughly. Normally that is... It's one of the coolest cars I've ever owned.


    1. Reading some other threads here and on German forums, it seems that the fuse box located under the right rear seat is often referred to as the 'rear or 'trunk' fuse box. And that there are NO fuses located close to the battery... So, your answer makes sense...

    2. I'll open the CPU box that was installed in the car when I switched polarity for a visual check-up... I'll go on Ebay to look for the Launch CRP129 code reader, too. Was yours expensive? Good to read that you needed to clear all codes after installing the replacement CPU. You did not mention that in your initial description of how you solved the problem...

    Sure hope that clearing all codes will restore my car to full-functioning again!

    3. Yup! Got hold of a CPU that has the exact same part numbers as my original one. From a W220 (sedan). Purchase of the fault code reader is a good idea...

    4. Earlier today I read a thread here about resetten 'the' CPU of the car by turning the key to position 1 and holding the gas pedal down for 5 seconds, etc. etc. etc. Do you think that might work too? It mentioned turning my steering wheel from full left to full right position too... No harm in trying that procedure too, I guess... Any experience there?


    Regards, Christiaan
     
  15. OP
    fast28

    fast28 Senior Member

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    Your Mercedes:
    SL55-conversion (R129) & CL63 AMG (W216)
    Yes you need to reset the adaption of the steering sensor after installing a new battery, full lock left to right and back to centre.
    For the Ecu install I cleared codes with the ignition powered, switched off, replaced Ecu and turned engine on and performed the steering adaption as above.
     
  16. Christiaan Soerjo

    Christiaan Soerjo New Member

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    So no need for the Launch CRP129 code reader to clear the logged fault codes? And to extinguish the brake lights that are now lit continuously?
     
  17. Craiglxviii

    Craiglxviii Senior Member

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    Your Mercedes:
    W215 CL500 Garage Queen; W211 E320 Avantgarde Estate Designo Edition
    If you like, the ICarsoft i980 or MB-II code readers are MB specific and are very good.
     
    bembo449 likes this.
  18. Westheath

    Westheath Senior Member

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    Last edited: Mar 6, 2018
  19. OP
    fast28

    fast28 Senior Member

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    Your Mercedes:
    SL55-conversion (R129) & CL63 AMG (W216)
    I would highly recommend reading what the fault codes are by any means to confirm a faulty ECU or any other problem with the car. The code I had was "no communication with ABS-BAS-ESP-PML ECU".

    The brake lights staying on can also be caused by a faulty brake light switch on the pedal.

    I sold my CL500 2 years ago so I am going by memory here. :)
     
  20. Christiaan Soerjo

    Christiaan Soerjo New Member

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    @Craigixviii:


    Thanks for the tips. I've made an online comparison between the Launch CRP129 code reader, the iCarsoft i980 & i980 II (both for MB) and MB Star and I've ordered the iCarsoft i980 II MB device. Should come in Tuesday March 13th, 2018...



    @fast28:


    Yesterday evening I gently pried open my original BAS-ESP-ABS-PML CPU module, which was easy due to the thin soft aluminum. A visual inspection reveals NOTHING. All components in as-new condition. No cracks in the PCB. No corrosion. No evidence of any moisture or water having entered the module at any time. It looks brand-spanking-new inside.

    So I've been thinking. You mentioned that you battery was charged the wrong way round inadvertedly and that was what caused your problems.

    My situation is slightly different. My installed new Bosch was just under the voltage that is needed to start the car. So I hooked up number two that was sitting right next to it as luggage in the trunk. The wrong way around.


    This should have resulted in either a 1) very low positive voltage fed to the car, b) a slightly negative voltage fed to the car (this is most likely since the 2nd battery was fully charged. The voltages cancel eachother out: +11.8 - 12.5 = - 0.7 V for instance...


    At this moment my theory and hope is that due to this reversed voltage my systems logged error codes, but since the car was exposed to this undesired electrical source only a very short time, no damage of the CPU was the result.

    Hopefully, after I have cleared (using my future iCarsoft i980 II MB code reader/eraser) the fault codes, all systems (ABS-BAS-ESP-ABC and my continuously lit brake lights) will have returned to their normal status quo and will be fully operational again...


    If not, I hope that a full scan of my car points me towards the source of my remaining problems... I'll keep you posted here. Hopefully to the advantage of future MB-drivers facing similar or the same challenges...



    Have a nice Sunday! Regards, Christiaan
     
    Last edited: Mar 11, 2018

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