Experienced my first solid 4WD light on the dash after having my Exy for over 6 years.
Just come back from a 10,000km round trip down to Brisvegas and back up to Darwin. Did three days on Fraser Island leaving Inskip Point onto the Ferry then up the inland road on the southern point of Fraser since the tide was very high and impassable along the beach route. The inland road is one of the worst I've driven on in a long time with ruts, giant boulders, loose sand and gravel and uneven levels of flatness.
Along the route a nice football sized rock decided to come loose and ram into the shielding around the tail shaft on the underbody, turning it all into a ball of squished foil wedged in and around the uni joint into the rear diff. This made a terrible noise as the heat shield was rubbing against the tail shaft weight balancers. It was dark so I pulled the shielding off and away from the tail shaft and bent it back into a shape away from any obstacles under the body. Instantly the Exy displayed the solid orange 4WD light. Didn't think to realise the light until we hit the beach access down ramp and decided to stop and investigate. No 4WD at all. Left it for the morning to do further fault finding.
The following morning pulled the Exy over a rut to enable easy access under the diffs. Discovered the nice rock had completely pulverised the electronic 4WD rear diff wiring loom. Which is oddly exposed to underbody collisions. The wires had been severed meaning no communication to the rear 4WD, and the steel mount or wire guard was squished nice and flat against the rear diff housing. Nice !!! I also noticed the extent of the heat shielding damage also but that is another story as is the mounting washer for the left hand rear suspension mount all bent like a bottle cap.
Managed to bend away, without snapping any metal mounts, the bracket and snip the wires and reattach using inline crimps with loads of electrical tape and zippy ties. I snug fitted all the wiring loom and mount back up and to the left side of the rear diff so nothing should rip out if it happened again. This resolved the 4WD fault. I was able to get back to beach bashing and both water and deep sand didn't cause any issue at all. I will have to resolder the wiring connections and do some modifcation to the diff housing when I am back home in Darwin to prevent further issue with underbody collisions.
Anyone else ever experienced solid 4WD light should consider eyeballing the wiring loom into the rear diff and checking for any damage before assuming it is just diff over heating. The wires are very exposed and any sort of poor contact or damage on the wires could cause intermittant 4WD failures. Its best to check under the black plastic wire guards, I didn't notice any visible damage to the wires until I carefully cut that back to expose the inner wires. One was barely connected and the other wire was completely severed.
Food for thought, luckily I had a well stocked tool kit 
Oh and I can't stress how useful having a can of WD40 in the toolkit can be over a thousand uses.
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X-1318 (c)
AkaZulu
2003 Ti-L T30, Polar White
Bling: Chrome factory Nudgebar, Spotties, Sunroof, Bonnet Protector, Towbar, X-Trail Brake Decal, HiTech Full Exhaust System, K&N Air filter, DVD/MP3/GPS/Bluetooth/TV/USB/iPod/Touchscreen TFT
