I am going through Doug's checklist to figure out what is wrong with the aux fan which never comes on.

Aux Electric Cooling Fan Checklist Jaguar XJ6 Series III

When I bypassed the circuit the fan motor worked, but I can't find the thermal switch to check if that is the problem.

"The thermal switch is mounted nearly at the bottom of the right side radiator tank." Excuse my ignorance, but I don't understand what this means, my radiator expansion tank is on the left side and I can't see a thermal switch under it.

I am looking for something that looks like the attached pic, right?

 

It's not in the expansion tank but on the lower rear rhs of the radiator. That is not the picture of it. That's a thermal switch on the intake manifold you show. It's a big brass plug with 2 terminals on it.

 

Can I see or access it from the top, or should I attempt to get to it from under the car? Thanks!!!!!

 

the problem is usually a bad fuse for the fan, the fuse is located in the 5-fuse box next to the brown coolant tank on the driver's side.

If the fuse is fine, then it is the Red relay mounted to the radiator support also on the driver's side.

if the Red relay is fine, then you need to remove the Auxiliary (electric) Fan mounted under the front bumper and test it directly to the battery;

if the fan is fine, then it must be the Thermo-Switch mounted to the bottom right corner of the radiator, in the passenger side. You will need a flashlight to see it, it is way down, and you need to remove the air filter front "trumpet" to be able to see down.

Not easy to remove the thermo switch with the radiator in place, but it can be done, you will need a 24 mm open end wrench if I recall correctly. But if you reach the point that the thermo switch needs replaced, then wait until you buy it to find the correct size wrench.

the following ilustration courtesy of SNG Barrat USA store.

SNG Barratt - The Ultimate Jaguar Parts Specialist

 

Is that it right in the center of the pic (attached)? Will it start pouring coolant when I unscrew it to test?




thermal switch

 

yes, that is the thermo switch, (see yellow arrow in picture)

yes, coolant will start pouring out big time, so put a deep pan underneath it.

when replacing the new one, add some Hylomar to the thread to prevent any leakage.