manross

UPDATE: Looking around the net I came across a site showing how to convert a led Db9(?) bulb to correct the polarity problem. That caught my attention. In Mercedes infinite wisdom they hooked the wiring to the map/courtesy bulbs reverse to the norm of the tip of the bulb is not positive, but negative. When I thought I was following correct polarity practices I in fact hooked the led backwards. The led bulbs I used still tried to work, but in that short time it took out the diodes. I replaced them this evening and will try it out tomorrow. I'll post an update afterwards.

Short history: I have converted my car over to leds throughout. Only thing not changed was the map/courtesy lights below the rear view mirror. Up to this point I didn't have one problem. Well that all changed when I bought two of those springy tubular leds that fits between the power posts. At this time (few months ago) there wasn't any of the direct replacement bulb to led lights. So the springy tubular leds I bought replaced the bulb holder of the regular lights. I made some contacts and put the leds in following polarity rules. Hooked the battery back on and the leds briefly lit and went out. I checked to make sure that they were making contact and that the polarity was right and they felt pretty warm. I noticed at this time that the leds lable said non polarity sensitive. Bull!! I pulled them out and put together the bulb holder and replaced the bulbs. No lights...crap. I had a bunch of other projects going on so after a few months it was time to repair them.
When I took apart the light fixture I checked the switches, power input, ground etc. When looking at the control board, I found my problem. The two power diodes (half wave bridge??) were burnt. One was disintegrated. Can anyone tell me the rating of these diodes? I can make out a 5 blank then maybe 11. I figure I can replace them with about any at least 12v rated power diodes with the same physical size. If anyone would happen to know or have a spare board that could get me a number off of them it would be appreciated. Here are a couple pictures


Contol board



Close up of component location