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Mercedes Benz 190D 1985 (W201)
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90 Posts
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Hi guys!

This is me again with my 190D 1985.
the last days has been raining straight here in Cali. Reason why I need to check what could it be wrong with my rear defroster. When you push the rear defroster on the right side the light come up just when pressing it, at the moment you release pressure it comes off. Also rear defroster doesn't work!! Is there any way I can check it? Bad switch? I checked fuses and everything seems to be ok. Any idea?!
Also there's something I've been asking for so long.. Why my antenna doesn't go down when pressing the dasboard switch?? I does when turning on/off strereo (by the way.. It's loud when going down!)
hope you guyscan help me with those little problms.

Regards.
 

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C140 W140 C126 W201 W116 W210 W163 W251 R129 R170 928S 944S GTV6
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363 Posts
It's fairly easy to test if you have a multimeter. There are two insulated copper bands running from underneath the back pillar inside trim to either side of the rear glass heating element. When the switch is on, you should be able to measure just a little bit under battery voltage there. If you have that, then your next step is to check the heating element itself.

On the 190 this is directly on the inside of the class, you can feel the brownish lines running your fingers over them, they are not really protected and with age often deteriorate. Disconnect one of the copper bands supplying power to the element and switch your multimeter to measure resistance. The resistance between the two connectors should be very low...under 10ohm I would guesstimate if it is a 125W element AFAIR.

If you are somewhere much higher or have no continuity at all, you have one or more breaks in the element. You could try to identify the location of the break by leaving one side connected to the multimeter and taking measurements with a sharp pointed probe along the lines running across the element. You will gingerly have to scrape off some of the insulation/oxidation that covers them, and if you are not careful doing this, you can actually cause more harm by scratching them through. If you can locate the location of one or a few breaks, there is a kind of liquid repair kit sold in autoparts stores that will bridge little breaks and make it work again, however, in my '84 the element was deteriorated to the point where I probably would have had to buy 200 of those tiny little bottles and then had no heating element but only repair fluid left :p

In that case, there is really no other option than a replacement glass. If you go aftermarket, usually around $300 installed from a safelite or payless glass kind of company, a lot more at the stealership.

Hope this helped!
--Zax
 
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