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#1
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Temperature gauge backlight light bulb
Fixed my odometer on the 190D. Would like to fix the backlight on the outside temperature gauge while the cluster is out. It does not come on at night and the bulb is found to have burnt.
What is the part number of the small light bulb that is soldered onto the PCB board? Is it 12v? Can I replace it with one of the small light bulb, say, the one in the climate control unit? The size is roughly the same, just need to straighten up the legs.
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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed. W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html 1 X 2006 CDI 1 x 87 300SDL 1 x 87 300D 1 x 87 300TDT wagon 1 x 83 300D 1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry. |
#2
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Do you want to solder it to the PVB? the legs of a bulb such as for the climate control seem very short to me.
Part # from ******** az: 0008250094 Instrument Light; Frosted Bulb for Instrument/Dashboard Lights $0.69
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1996 E320 since 1/16/08, 171K miles as of Feb 2011 --------------------------------------------------------- 1989 300CE - R.I.P. Dec 29 2007 Other MBs (sold): 1992 300E-24 - 1979 350SLC - 1984 230E - 1990 300CE |
#3
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Quote:
12V 60mA Microlamps (2-Pack) Model: 272-1092 | Catalog #: 272-1092 $1.79 for two This bulb is also a suitable replacement for the $19 bulb used in Volvo seat heater switch illumination! |
#4
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Why not just replace with an LED and a resistor?
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-tp 1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS 1988 560SEL "Gunther"- 190K passes anything except a gas station 1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition |
#5
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I thought about that if I cannot find a sutiable light bulb. What is the current drawn? Shall I limit the currrent to be below 40ma?
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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed. W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html 1 X 2006 CDI 1 x 87 300SDL 1 x 87 300D 1 x 87 300TDT wagon 1 x 83 300D 1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry. |
#6
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The problem is that LED's are effectively not adjustable with regard to their light output because the MB interior lighting circuitry is voltage variable not current variable. The circuitry for the interior lighting varies the voltage levels to achieve dimming effect with incandesant bulbs. LED's have a threshold voltage and either turn on if it is exceeded and turn off it is not. An LED's brightness is affected by the flow of current to it.
Another potential issue would be the positioning of the LED, most LED's are not omni directional in the orientation of their light output. Usually there is essentially a "primary cone of light output" that could require a specific placement of the LED to maximize its ability to illuminate the entire display area. Last edited by Billybob; 01-29-2010 at 06:17 PM. |
#7
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Yeah, I forgot it was a dimmed circuit. You actually can dim LEDs quite a bit, but at some point they just cut off. LED dimmers actually work by pulsing the voltage to the LED instead of reducing it.
So, your points are quite valid. The dimming will work to a point, then it will just shut off. Although, with a resistor in series with the LED, you get your current drop when you dim the voltage. Trying to get the right value resistor might be a pain. Perhaps bench test with a potentiometer to find the sweet spot? Y'know..... The easiest thing to do might just be go to Pick n Pull and grab one. I've got several of them and I don't think I was charged for any of them.
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-tp 1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS 1988 560SEL "Gunther"- 190K passes anything except a gas station 1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition |
#8
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Quote:
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#9
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In that case, a second resistor with one leg connected to ground could be used to create a load after the first resistor which would in turn provide a more substantial voltage/current drop.
Now what would be totally AWESOME is if you used a two color LED and made the display change colors when you get below freezing.
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-tp 1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS 1988 560SEL "Gunther"- 190K passes anything except a gas station 1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition Last edited by tinypanzer; 01-29-2010 at 11:05 PM. |
#10
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I found a spare temperature gauge from a w126 chasis with a broken LCD but good light bulb. I swapped the light bulb and now I have backlight. I think you need to have a small and low wattage light bulb otherwise it may bust the electronics. It is all surface mounted electronic stuffs, I am impressed.
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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed. W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html 1 X 2006 CDI 1 x 87 300SDL 1 x 87 300D 1 x 87 300TDT wagon 1 x 83 300D 1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry. |
#11
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Clarify please, does the outside temp gauge backlight bulb need to be soldered, or does it plug in as other cluster bulbs do? Thanks.
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1988 California version 260E (W124) Anthracite Grey/Palomino Owned since new and still going strong and smooth MBCA member Past Mercedes-Benz: 1986 190E Baby Benz 1967 230 Inherited from mom when she downsized 1959 220S Introduced me to the joys of keepin' 'em goin' There are only 10 kinds of people in the world--those who understand binary and those who don't |
#12
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You need to open the cover and solder the new one in. On the 190D, the bulb is buried under 2 flat ribbon cables and is a bit of tough to get to. It is not a plug in.
__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed. W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html 1 X 2006 CDI 1 x 87 300SDL 1 x 87 300D 1 x 87 300TDT wagon 1 x 83 300D 1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry. |
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