What are you trying to accomplish?
There are three temperature sensors for your year XJ. The sensor for the gauge (or idiot light) is located on the left (driver's side) rear corner of the head. The sensor that provide data to the ECU for engine controls is located down low on the driver's side of the block, below the manifolds. The sensor in the driver's side radiator tank isn't really a sensor, it is (as noted) nothing but an ON/OFF switch, and all it controls is the auxiliary cooling can.