Have a tail lamp on a BMW that corroded away, forcing you to solder straight to the lamp assembly? Fear not! There is a very special tool you can use, along with dielectric grease, to combat these BMW plagues!
both methods will work scraping off the rust and the soldering one in my case I Hope this helps, I had the same exact problem on my 540i E39 on my passenger side tail light every light would work but one, my turn signal would not blink , I tried switching sockets from my working tail light to the non working one and no cigar, A Friend of mine tested the board on the tail light with some alligator connectors and a small battery all lights worked so that told me that she board is good ,I noticed the same corrosion on some prongs what I did , I wrapped a butter knife with a piece of paper towel and sprayed PB Blaster inside the tail light connector I let it soak for about 2 mins all You do is rub the connectors with the knife and towel until it looks clean kinda silver looking again , just repeat as needed Pb blaster brakes off rust that did the trick for me .
You have to understand WHY the original plugs corrode....then you can fix the issue. Soldered straight is tacky and cutting corners. When you cut corners you know have 2 corners...that applies with alot in life as well
