Remove the glovebox entirely. Remove the airbox in the engine bay Make a hole in the side of this rubber gromet (or as I did cover the cable in washing up liquid and manage to push it through alongside the existing loom) and feed it through using a coat hanger or something Took me half a day, most of my knuckles, and a ton of swearing
Just make a slit vertically above the hole for the main harness, feed the cable through that into the engine bay, if you don't want the hassle of squeezing it through with the main harness. Good job RSphil for managing that - wasn't going to happen on mine.
Really weirdly because the rubber is sort of double skinned - I tried for nearly two hours to cut a new hole in it. I made one and I could get a coat hanger through it - but the cable would just not go Eventually I put a coat hanger through the main loom hole - taped the cable to the end of it - covered it in washing up liquid for lubrication and managed to pull it through lol Shitty job though - I've done dozens over the last 20 years and never done one that awkward, my back was killing me from being laid upside down for the whole afternoon
Oh yeah, last week I tackled it fast, coat hanger tip was awesome, Took a stainless TIG rod and went straight though, bit of tape and voila. Thanks for the tips! Hope to contribute soon!