Only one engine harness on this car. There is a second wire harness that is sometimes refered to as the battery cable harness. It consists of a battery cable (duh) and three other wires. If I remember correctly, the three wires go to oil pressure sender, oil low quantity sender, and starter lockout input. Usually the battery harness is not problematic, although crumbling insulation can fall into the oil filter housing during an oil change if your'e not careful. (these three wires run across the firewall just above the filter housing....) Engine wire harness replacement is not difficult, good DIY article with pictures here at MercedesShop.com

J. M. van Swaay