Update time and...who's a dickhead then? That'd be me! At least I have the seeds to admit it. In a recent post I mentioned how a leak in the boot of my X had caused all manner of issues which I had managed to overcome by repairing the leak and then stripping the rear fuse panel to dry it out. Well as it turns out, Mr. Mechanic over here never double checked the reassembly...the old saying of measure twice, cut once really does apply in this case. As it happens, I had not securely clipped in one of the many plugs on the rear of the fuse panel (the fuses slot into these plugs) and obviously once the fuses had been reseated this resulted in an intermittent connection of two fuses in particular. One was for the transfer case control module I assume since the descriptive image on the fuse card is of a gear. The other fuse was for the VAC, more specifically the rear (third row seating) temp sensor as described by the fault code (I use BMWhat). Fuse numbers 92 and 93. So thank you guys for the opinions offered and I apologize for being a numpty.