It really does depend on the year of your XJ. My '01 Aux fan is activated when the engine temp is high enough or when the pressure in the AC surpasses a threshold. With my '96, the Aux fan is on when the AC is on, regardless of pressure. This all affects what is happening at slot #2 (if memory serves correct) in your relay. I'd poke around with a multimeter to get a sense of what terminals are hot, and at what times. That should help with sorting out how best to wire in your switch.

Mines a 2000. And according to the fuse block I have a separate relay for ac

as i said, jump in after the thermocontact. its the best way.
then you become the "thermoswitch", and the original will work regardless.

remember the fuse, as you are using a hot wire

yes... much easier

https://www.cherokeeforum.com/f67/ho...ght-way-94452/

however you should consider this instead of a SWITCH

https://www.cherokeeforum.com/f67/be...7/#post1046707

So, basically your saying I'd be better off throwing inna Taurus fan. Only problem, where am I going to get those controllers and stuff? My JY spray have that high class of cars

Also, if I was just going to cut all connections to the fan and hardwire it solely to a switch, what should I do with the wires I cut?? Meaning, tape them together, or tape them separately so they never touch.