Hey,

This may sound scary to do but I took the chance with my 99 ML320. I had a rat that ate the freaking main wiring harness under the dash and in the fuse box. I bought the same gauge wire and some clamps and also some those heat shrink wrapped. The reason i suggest this is because you have both ends of the cut wire. so if its easy to access then take your new wire same gauge or as close as possible then best to solder them but clamp works also and see what you can do. It took me couple of hours to find each correct end of the wire especially under the damn fuse box but in the end my cost was less than 10 bucks for the roll of wire and heated shrink rap thing. just an idea if esp if you are out of warranty.......