I have a 2005 X-type and it suddenly went into limp mode. I lost the speedometer, the tachometer, and almost every warning light lit up. It was a dry evening and had been dry for a week or more. When I checked the codes there were a dozen or so and most were CAN related majority for engine and transmission. I reset the codes and got about 7 miles before reoccurring. Both the battery and alternator have checked out fine. Research has turned up two common issues of the wire harness of the gauge cluster. Han anyone else had this issue and successfully remedied it. What can I do to start diagnosing or at least eliminating causes.

 

CAN communications are usually carried on twisted pairs of yellow and green wires between the various CAN connected modules.
I think you should normally measure about 200 ohms of resistance on the CAN line depending on which module as some are simply passing CAN through to the next in the chain while others act as a CAN hub or terminator.
There are some prior threads from other members that have methodically traced CAN wiring and taken measurements. You might want to do an advanced search to see if you can locate and read them to see if they might help guide you.

However, the best place to start is by downloading the schematic for your 2005 model, but be aware that 2005 saw a change in production so there are two schematics (up to 2005.25 and after 2005.25).
In the later pages (somewhere around Fig 20) is the CAN Bus layout showing you how the modules interconnect, connector and pin info.

Rodent activity under the hood is unfortunately common due to the use of vegetable based wire insulation throughout the looms.
Modules to pay particular attention to a re the ABS module, TCM and instrument cluster.

TCM is known to suffer some water ingress following the loom down from the heater assembly. Water overflows the cabin filter intake if the scupper drains are blocked and that can lead to a damp carpet in the foot well and water tracking along the cable loom to the TCM.

If you suspect the TCM might have copped some water, you can remove it, open it up and check if the internal side of the main connector or PCB shows any sign of some corrosion which can cause some electrical current leakage.
That corrosion residue can be cleaned back with a small stiff brush (tooth brush) and/or cotton buds using some Meths or Isopropyl alcohol.
If the corrosion has take too much of a hold there might be some connector pin or copper track damage that might need addressed.

Good luck with your hunt.