I noticed that the rear window defroster of my '95 9C1 had been working intermittently over the last few months. Yesterday I had an early morning appointment and heavy dew. When I squeegeed the windows they just fogged back up seconds later. The rear window defroster did not work at all even though the indicator light was lit, and I couldn't safely back out of my driveway until I heated up the interior of the car. Time to find the problem and kill it. I read several posts here about it and tried some suggestions. The least useful suggestions concerned the "relay" in the fuse panel. It's a circuit breaker, not a relay. The most helpful was Cheprice's link to a wiring diagram of the circuit (Thank You Cheprice). Many cursewords later, I found the culprit. On the left side of the rear windshield (left side of the car) is a terminal to which a black wire with a white stripe attaches. This is the +12V supply for the defroster. The right side of the rear windshield connects to a ground. I got no voltage on the left side connector when I had the defroster turned on (indicator light lit). That black wire with a white stripe is only about 20 inches long and it connects to a purple wire in the trunk. I could probe into each end of the connector and I found that the purple wire was supplying +12V but it was not getting through the connector to the black wire with a white stripe. I could not disconnect the connector. It looked normal on the outside but apparently it had developed resistance, had gotten very hot when the defroster was on and melted the plastic together inside and somehow the metal parts inside are not making contact anymore. I cut it off and connected the wires together with a common crimp type connector. I connected a test light to the rear windshield left side terminal and it stayed on for ten minutes (as it should) then it stayed on for 5 minutes when I turned the defroster back on (as it should). The crimp type connector did not get warm so it is a good connection. No dew this morning so no definitive test but I am sure it will work. Here is a picture of the culprit. I hope this helps somebody.
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