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Thread: E32 fuse box fire under rear seat -pics

  1. #1
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    E32 fuse box fire under rear seat -pics

    Apparently the fuse #46 is for the rear windshield heater is in many case the cause.

    http://s52.photobucket.com/user/pete...fire4.jpg.html

    Comments:
    The rear window heater fuse may have smthg to do with the fire in Pete's car, after I saw the way the fuse body plastic melted for the rear window heater (fuse 46) yesterday. Any suggestion of what better to do with that fuse? like reducing the rating if the heater coil doesn't draw near 30Amp? or remount that fuse away from other fuses and use a different kind of fuse like the glass tube type? I think there is a period of time where the fuse turned half melted due to usage, and had increased resistant. Thus the fuse element would start to heat up and either melt, or ignite the surrounding plastic.

    Patrick C 88 750 159K
    ---------------------------------------
    Comment by Johan:
    Problem : At some point the fusebox caught fire. Probably due to corroded contacts. That's exactly why I always replace the fuses and clean the contacts of the fuse holders in an older car.
    ----------------------------------------------------------

    Same happened last week in Germany.
    Last edited by shogun; 08-09-2013 at 11:04 PM.
    Shogun tricks and tips for the E32 series are HERE!

  2. #2
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    some more pics of fuse box fires caused mainly by the rear window heater relay (?)
    http://forums.bimmerforums.com/forum...ms-in-pictures

    Layout Of Front Power Distribution Box
    Layout Of Rear Power Distribution Box
    Auxiliary Relay Box
    Fuse Assignments
    Component Index>>Component Locations>>Component ID
    http://ww2.justanswer.com/uploads/rm...841_aFinal.pdf
    Last edited by shogun; 08-10-2013 at 12:10 AM.
    Shogun tricks and tips for the E32 series are HERE!

  3. #3
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    And more pics of fire caused by corroded contacts http://www.bimmerboard.com/forums/posts/451140/
    Fuse box rebuild info http://bmwe32.masscom.net/johan/fuse...ox_restore.htm
    Shogun tricks and tips for the E32 series are HERE!

  4. #4
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    Wow, makes me glad I live in a moderate climate, have never used the rear window heater, probably never will. One bullet dodged.

  5. #5
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    Quote Originally Posted by shogun View Post
    And more pics of fire caused by corroded contacts http://www.bimmerboard.com/forums/posts/451140/
    Fuse box rebuild info http://bmwe32.masscom.net/johan/fuse...ox_restore.htm
    Thanks for posting. That fuse box rebuild is great stuff.

    On my 91 e34, the blower motor fuse smoked a bit but luckily, I caught it in time so I was able to fix it.
    demet

  6. #6
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    Electronics Under the Rear Seat - pics, names, locations and functions
    http://bmwe32.masscom.net/johan/elec.../rearseat.html
    Shogun tricks and tips for the E32 series are HERE!

  7. #7
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    Okay, no more rear window heater...

  8. #8
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    ^ Yeah, I am almost thinking the same. I already replaced it fuse once. Now I want to go through all the relay/fuses boxes and clean contact. Scary stuff.
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  9. #9
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    Good Morning All... Just had this happen last night to an E32 I've owned less than 48 hours. Haven't torn anything apart yet (haven't even decided whether to tow it home or call the insurance company). I'll research more when I get to a real computer, but does anyone know off the cuff how much of this section of wiring harness can be switched out "plug and play" if I can find a parts donor for the wiring and control units/relays? I've had dozens of BMWs over the years, but have been out of the fold for a couple years...

  10. #10
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    First inspect and see how much damage there is, maybe just minor things. The fuse box and relay holders you can get out, but there is a lot under the rear seat and here- just for info- some pics we made when parting out a 750 and we removed all cable looms
    http://www.bimmerboard.com/forums/posts/270025/
    Shogun tricks and tips for the E32 series are HERE!

  11. #11
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    thanks! the relay and fuse blocks and components would all need replaced, and the section of wire loom that's nearest the door has a few melted wires as well. not sure if that removes easily. i pulled the car home and tried to look it over as well as i could without disturbing anything... but don't want to remove anything until i decide whether or not i'll be filing an insurance claim.

  12. #12
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    Maybe you can get a used box with wire loom pigtails, check in the E34 classifieds section, there are some people parting E34 and E32
    Shogun tricks and tips for the E32 series are HERE!

  13. #13
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    and the next melted fuse box under rear seat, E32 730 M60B30, as usual rear window defogger fuse http://www.files.leder-wagner.de/BMW/IMG_schlimm.JPG
    He was lucky, he only noticed that the rear defogger did not work anymore and checked for the fuse.
    Typical, again the rear window defogger. That draws a lot of power and when the contacts of the relay and fuses are not clean, that melts away.
    Use contact cleaner and enhancer.
    SINGLE COMPONENTS FOR REAR CARRIER
    01 MODULE GUIDE FOR CARRIER 1 61131379555
    02 Instrument carrier, rear left 1 61131378539
    02 CARRIER ADAPTER 1 611313881200
    For vehicles with Lift-up-and-slide-back sunroof, electric=Yes
    04 PLUG CONNECTION ADAPTER 1 61131382537
    05 PLUG CONNECTION ADAPTER 1 61111382133 ENDED
    06 Cover 1 61131388012
    07 MODULE BOX 1 61131388011 ENDED
    08 Fuse carrier 4X 61131378982
    http://www.realoem.com/bmw/enUS/show...diagId=61_0583
    Shogun tricks and tips for the E32 series are HERE!

  14. #14
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    Just a warning, do not install larger fuses than originally specified. Unfortunately a standard automotive fuse will take more than the rated current for a specified time before it pops. Here some info https://www.pecj.co.jp/en/fuse/outline/p3.html
    copied from the net: The speed at which a fuse blows depends on how much current flows through it and the material of which the fuse is made. The operating time is not a fixed interval, but decreases as the current increases. Fuses have different characteristics of operating time compared to current. A standard fuse may require twice its rated current to open in one second, a fast-blow fuse may require twice its rated current to blow in 0.1 seconds, and a slow-blow fuse may require twice its rated current for tens of seconds to blow.
    Fuse selection depends on the load's characteristics. The fastest blowing fuses are designed for the most sensitive electrical equipment, where even a short exposure to an overload current could be very damaging. Normal fast-blow fuses are the most general purpose fuses. A time-delay fuse (also known as an anti-surge or slow-blow fuse) is designed to allow a current which is above the rated value of the fuse to flow for a short period of time without the fuse blowing. These types of fuse are used on equipment such as motors, which can draw larger than normal currents for up to several seconds while coming up to speed.
    Shogun tricks and tips for the E32 series are HERE!

  15. #15
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    Also should probably suggest to always use OEM electronic bits in the E32, its already a very particular car as is. A no-name brake switch burned my car down. Only install high quality components!

  16. #16
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  17. #17
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    Quote Originally Posted by shogun View Post
    How can BMW not be held liable for this? It seems like every E32 is a ticking bomb because the electrical system is inadequately designed.

  18. #18
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    well, the cars are about 30 years old now, we have to make preventive maintenance to avoid this, corroded contacts, old fuses etc, look how Johan did http://bmwe32.masscom.net/johan/fuse...ox_restore.htm
    E32Fan once mentioned:
    First question is - was the rear window defroster running prior to the fire starting? If yes, then the cause may be corrosion at the fuse contacts which causes the resistance to rise. Then the heat is shared between the fuse and the rear window heater.
    30 amps x 12 volts = 360 watts before the fuse blows, and this is a lot of heat in a small area so ignition can result. Imagine a 100 watt light bulb in a closed box.
    ------------------
    https://www.bimmerforums.com/forum/s...p?1612897-Fire

    Stabilant 22A Electrical Contact Enhancer
    Model: All BMW
    Complaint: Connectors which carry low current are more likely to form deposits which affect the resistance of the circuit through the plug connector. Depending upon the particular circuit these deposits can cause malfunctions and consequently activate warning lamps and check control indicators.
    Remedy: Part replacement can temporarily stop the problem. If the connector is the problem then without disconnecting the connector measure the resistance of the circuit running through the connector to make sure the connector has a high resistance. A good resistor will have close to 0 ohms resistance. Visually examine the male and female terminals in the connector housing by removing them. Look at the integrity of the wire crimps, and in some male terminals the integrity of the weld of the male pin to the terminal. Then reinstall. With a zero residue electrical contact cleaner liberally spray the male and female connectors, and allow the air to dry. Apply Stabilant 22A to both male and female terminals so they are saturated, and reconnect the connectors while they are still wet. When the Stabilant 22A dries it will leave a thin coating of polymer film which is conductive between mating surfaces, and is non-conductive between adjacent pins. It can also prevent the formation of more harmful deposits.
    Shogun tricks and tips for the E32 series are HERE!

  19. #19
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    Quote Originally Posted by shogun View Post
    well, the cars are about 30 years old now, we have to make preventive maintenance to avoid this, corroded contacts, old fuses etc, look how Johan did http://bmwe32.masscom.net/johan/fuse...ox_restore.htm
    E32Fan once mentioned:
    First question is - was the rear window defroster running prior to the fire starting? If yes, then the cause may be corrosion at the fuse contacts which causes the resistance to rise. Then the heat is shared between the fuse and the rear window heater.
    30 amps x 12 volts = 360 watts before the fuse blows, and this is a lot of heat in a small area so ignition can result. Imagine a 100 watt light bulb in a closed box.
    -----------------
    Really ridiculous if you ask me, I’ve never heard of a car needing fuse box maintinence. My 24 year old Toyota celica does not care for such things, silly that BMW does. I’ve become very suspect of BMW electrical systems, they always seem to be poorly designed. E46 had a grounding problem in the tail light harness that caused it to melt down eventually. BMW only fixed for free because US government forced them to do so. E9x suffer from faulty blower motor harness wiring that can also melt down a cause vehicle fire, again BMW addressed the issue for free because the US government forced them to. I already reported my previous 735 fire to BMW N.A. they did not seem to care very much. Disheartening to say the least.

    Will the fuse contact cleaner prevent fire? Will changing all the fuses be better for the electrical system?

  20. #20
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    Yeah, its a major design fault. But I will add that corrosion under the seats could easily be created by batteries that are not being vented. When installing one, its CRITICAL it has a vent tube hooked up. When batteries get warm and are charging, they outgas. That gas is very corrosive. Usually this is not an issue in most vehicles, but those gases are trapped under the rear seats. So that is probably one part of it. There is a grease you can by that enhances contacts while reducing corrosion. Its common to use in telecom for outdoor hubs, etc. I used it inside a starter when I rebuilt it and on the large battery contacts (not the battery itself, but the major grounds, etc.). The key is to use very, very little. Just an invisible coat and it help to have a heat gun to really work it into the microscopic surfaces.

    https://www.amazon.com/gp/product/B00HDF9EXE/
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