1995 e300 diesel electrical sillyness

Discussion in 'Electronics' started by carat 3.6, Aug 28, 2011.

  1. carat 3.6

    carat 3.6 MB Enthusiast

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    96 e300d, 88 w124 superturbodiesel, 90 bmw E30 v8, + "others"
    Hello all.

    My daily runabout w124 e300 diesel estate, in which a fault is unheard of, has been playing up this week in a rather un-mercedes like way. The problem is electrical and is causing me a great deal of head scratching, the car is still in constant use so really needs sorting out. Below is a rough story of the problems.

    Fault number one: With the car running, pushing the brake pedal cause's all dashboard instruments and gauges to stop working, and a buzzing sound comes from under the dashboard. Upon releasing the brake pedal, everything returns to normal. :crazy:

    I used the car for 2 days like this, but it then progressed that upon releasing the brake pedal the dashboard would not return to normal. It would only return after a breif rev of the engine, and I also noticed that the brake lights had stopped working. That afternoon I checked the car for anything obvious, but came to the conclusion that there was a short in the brake light wiring. Needing to use the car that evening, I temporily ran a new wire from the battery down to the brake light switch, and then to the brake lights at the back to get them working. I also disconnected the original brake light wiring just in case of a short.:eek:

    This cured the problem till next day, when fault number 2 appeared!:doh: Now with the ignition on all the warning lights iluminate as normal but the bulb failure, low washer fluid, low coolant, low oil level, and low brake lining warning lights were dimmer than the rest. And they got dimmer and dimmer throughout the day everytime I started the car, till they can barely be seen.
    Next morning I examined the wiring behind the dashboard, under the fusebox, and the fusebox itself. I couldnt see a problem, no blown fuse's or dodgy wires, so I decided the problem may be the light control unit. I swaped this for a known good unit and it made no difference to the problem, so I re-fitted the original back in the car, and this led to.......

    Fault number three:(: Now the passengers side headlight has stopped working on dipped bean only! The bulb and the fuse are ok, but there is no power going to the light itself. Main beam and sidelights work as normal, and the bulb failiure light is now on constantly.

    This needs sorting out before it gets out of hand! My only theory at the moment is that the light control unit has a bad earth? I wont have time to pull the car apart and check this till tuesday, so any ideas are most welcome.

    If it develops another problem before tuesday I will post it here. :mad:

    Any ideas guys??????????
     
    Last edited: Aug 28, 2011
  2. Tiff

    Tiff Active Member

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    Do you have a towbar?
     
  3. OP
    OP
    carat 3.6

    carat 3.6 MB Enthusiast

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    96 e300d, 88 w124 superturbodiesel, 90 bmw E30 v8, + "others"
    No, it's never had one.
     
  4. OP
    OP
    carat 3.6

    carat 3.6 MB Enthusiast

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    96 e300d, 88 w124 superturbodiesel, 90 bmw E30 v8, + "others"
    Wtf???

    I had a half hour spare this morning, so I did some more poking about in the fuse box. I ran a new temporary earth wire to the light control unit, which made no difference so I took it off again. Then I noticed 2 relays at the back of the fusebox, under the scuttle panel. These have a blade type fuse in both off them, and sure enough one had blown. So I replaced the fuse.... No difference! At this point we needed to use the car, so I put it back together and got on with our day.:wallbash:

    Now, at 11 pm today, we get in the car to come home from a party with freinds, and the car has cured itself! No warning lights on the dash, and all lights are working again!

    Is it possessed? :dk:
     
  5. trapperjohn

    trapperjohn MB Enthusiast

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    You obviously have a "girl" 124. The girl 124s get a bit moody from time to time.
    But take them to a party^ or buy them some new shoes and all becomes right in their world.
     
    3 people like this.
  6. OP
    OP
    carat 3.6

    carat 3.6 MB Enthusiast

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    Maybe, I should buy her a new set of floor mats, just to make sure. :D
     
  7. Ian B Walker

    Ian B Walker MB Enthusiast

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    Don't buy seat covers without consulting her. ;)
     
  8. OP
    OP
    carat 3.6

    carat 3.6 MB Enthusiast

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    If anybody needs me I'll be outside stroking her bonnet star, and whispering sweet nothings in to her air intake! :thumb:
     
    3 people like this.
  9. OP
    OP
    carat 3.6

    carat 3.6 MB Enthusiast

    Messages:
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    Location:
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    96 e300d, 88 w124 superturbodiesel, 90 bmw E30 v8, + "others"
    She's got the hump again!

    It must be that "time of month" for my girl s124, cos the wagon has decided to throw a electrical strop again.:rolleyes:

    Fault no1 was the ilumination for the entire dashboard packed up, this was traced to the "pointless light control resistor type thingymajig" hidden inside the instrument cluster. It has no function what so ever that I can think of, so I removed it and fitted a 10amp fuse in it's place. Problem solved untill next morning when........

    Fault no 2 the fans for the air conditioning want to intermittantly start up by themselves. This was found to be caused by broken insulation on the wires at the temp sender, so as a temporary fix I wraped them in pvc tape. I will make a proper repair with new wire, when I remove the inlet manifold to change the fuel lines next month.

    So to keep my mistress happy I bought a few cans of paint and some bumper filler, and removed some of her wrinkles. No more scratced rear bumper.


    [​IMG][/IMG]


    Should keep her happy for a while....
     
    Last edited: Apr 29, 2012
    1 person likes this.

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