I can't tell anything from the photo. If it's a simple break in the wire, this is what I'd do: strip the ends; slide a piece of heat shrink tubing over one of the wires; clean the bare wire ends; twist them together tightly; solder the connection, ensuring a proper solder joint; slide the heat shrink over the soldered joint and apply heat. Viola.

Hope this helps.
Bill

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1998 E300 +310,000K
1996 E300 +460,000K