I have a 1984 300D W123. I have been looking for a replacement combination gauge for the instrument cluster for it and the printed circuit board they are mounted to. (You know, the fuel, oil pressure, and temp gauge on the left side of the instrument cluster) My car is a Euro version non-turbo (with A/T and dealer added A/C). So, no tachometer. Just the big oversized clock all by itself on the right. Anywho, the big ol' round primary multi-pin plug on the back of my instrument cluster has 15 holes and there are 15 pins on the printed circuit board. (Also, there are 16 wires leading into the plug) Most of the used instrument clusters I have located on eBay, etc. have 14 pins and there is a gap where there would be a 15th pin. Anyone know why mine has 15 and most others have 14? And what the differences in the circuits and components are for 15 pin versus 14? Also, there is a square black relay on the back of my instrument cluster on the printed circuit board right next to the dimmer rheostat and below the oil pressure gauge fitting. Many of the used instrument clusters do not seem to have this relay. What is it?