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W124 Interior bulbs blowing - why?

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by Molesworth2, Mar 27, 2012.

  1. Molesworth2

    Molesworth2 Guest

    I bought a 1993 W124 E220 coupe a couple of months ago (110k miles) and this forum has been great for fettling advice. But I have now replaced three interior bulbs (two on heater controls, one on auto gearbox indicator light) and now a bulb on the instrument dash has blown. Is there a likely cause for so many bulbs to blow?
     
  2. television

    television Always remembered RIP

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    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    Do check that the running voltage of the car is no more than 13.8 volt,
     
  3. wireman

    wireman Senior Member

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    Your Mercedes:
    nice 201 2.5D 1993 & very nice 129 SL500 1994
    My 124 lost each lamp over my first winter, I think that the short time between sequential failures is an example of just how good the manufacturing quality of the small bulbs is, the replacements I used were spec'd for 3000 hours but that is not including cold switching effects which will shorten the lamp life significantly. Typically if they are all from the same batch they will all die at about the same time.
    Iv'e just replaced most of them again after 6 years and 110k.

    Beware that the T 1 1/2 wedge base lamp is available in several ratings, the 1 watt will melt some of the plastic if inadvertently installed in the control knobs, I used 0.4 watt for them all.

    Mine came from CPC, stock code SC00352 £3.71 for 10.

    Dodgy alternator brushes can cause voltage transients which wont be particularly good for any lamps.
     
  4. television

    television Always remembered RIP

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    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    I use the same ones from CPC Ring RU509T you have to squeeze the contacts together a bit for a good fit
     
  5. OP
    Molesworth2

    Molesworth2 Guest

    Voltage Too High?

    Many thanks for the quick, helpful replies. Minor delay while I sourced a multimeter! Checked voltage at battery: 12.3V without engine running, when idling it was showing 14.3V. Is that too high?
     
  6. television

    television Always remembered RIP

    Messages:
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    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    As long as it does not go over 14.3 at say 2k rpm then should be OK
     
  7. peterwhayward

    peterwhayward Senior Member

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    Your Mercedes:
    E240 classic est 2000 2.4
    If as you say the car is a recent purchase,it could just be that those bulbs were recently fitted (to help sell the car) and were cheap rubbish ones.
     
  8. television

    television Always remembered RIP

    Messages:
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    Your Mercedes:
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    Or as I had once, I took the cluster out to change 1, put it back in and 3 others had gone, just an age thing probably on the bulbs
     

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