does the stock electric fan only run with a/c on or should it run when the motor gets hot?

It runs when the a/c comes and when the engine gets to 217 degress when a/c is off,it is for the a/c. If the a/c sys is low on charge the fan will not come on even if the engine gets hot.

my xj is running over 220 but the fan does not come on.

I would hook your fan directly to the battery and make sure it works,if it does then make sure the a/c system is charged,if not bypass the low pressure cutout on the receiver drier,it could also be the relay in the dist box,the temp relay on the tstat housing,check fan first.