Auxiliary Fan Questions. 1994 XJS 6.0 V12
 

First, let me say, I don't think I've ever heard/seen/been aware that this fan has ever come on.

I know everything is working (with the thermo switch "out of the loop").

Is there a test for the switch?

Kirby Palm's book says a rewire can be done to bring the fan on when the ac compressor is on....but gives no details....if this is possible ,can anyone help here? Just seems a no brainer, that it should be on when the ac is running.....given the size of that condenser in front of the rad.

Maybe a thermo switch running at on, at say 180F would be a good mod, supposedly the original switch is on at 95C...203F...seems high to me.

Or is there a way of having the fan always on when the ignition is on?

Also, Palm states that for after shut down there is a rewire that will bring the fan on whenever it is needed during cool down....instead of the one shot "bootstrap" as supplied by Jaguar.

I'm not real good on electrics, but wonder if any or all of the above approaches are doable?

I'm in the beginnings of a complete coolant refresh. Awaiting infrared heat gun at the moment. Hence my current consideration of the aux fan.

I do not get a lot of stop start driving here in south central Nebraska, but last weekend we did a 600 mile round trip to Lincoln (to see A Prairie Home Companion show!)...Omaha.....Lincoln....back to Oxford. Lincoln is way bigger than anything around here so we were in stop/start mode in downtown Lincoln (outside temp 90F), ac on.

The needle would go the the extreme right upright of the N, and I think it would have gone higher if we had more severe traffic conditions.....which has got me wondering about the aux fan and the above questions.

Needle maybe wanders a little, so a bleed and a banjo bolt mod is on for the weekend.

FWIW, needle holds slightly to the right of the start of the N at 65 mph (outside temp 90F and ac on). Fan clutch seems fine and no junk between the condenser and the rad. Have 31K miles on it.....but I don't have any service records other than the Carfax.

I shall be going through all the Palm mods/service ideas through the coming winter.

Of course the "under tray" is missing...on my Christmas present list...looking at the underside of the front spoiler, I can only think that the under tray will help, possibly significantly, with the air flow in all conditions.....some what similar to having the air gaps around the rad closed off..there are good original rad seals still in place at the moment. Have not checked the flaps below the aux fan yet...will do that tomorrow.

Thanks,

Rob.
2006 X Type Wagon.
1994 XJS 6.0 V12 Convertible.
1987 XJ6 DD.

Hi Rob,

Did you ever get the answer you were looking for? I am in the same boat with my electric fan and I am interested in the best ways to improve controlling the system.

Thanks,
Paul

I would advise checking the switch


https://cimg8.ibsrv.net/gimg/www.jag...9ab474f301.jpg

By disconnecting both terminals, connect them together (a paper clip inserted into both terminals briefly) will cause the auxiliary fan to spin up, this should happen with or without ignition switched on.

If it doesn't then check problem with relay or fuse.

If it does spin up, but doesn't come on when temperature above N it could be a faulty switch.

I had a pattern part which was cheap, but expired after a short time.

Greetings from Omaha!

Auxiliary Fan Questions. 1994 XJS 6.0 V12
 

The Aux fan is controlled by a thermoswitch, according to engine coolant temperature, it has no bearing on the A/C condensor, the freon does not run through the radiator or the engine, completely separate systems. The aux fan will only kick on when it reaches the switch setpoint, you probably wont even notice when it goes on because it runs on an electric motor not the fanbelt, and it doesn't take any power from the engine. It has constant power to the switch therefore it is possible for the fan to kick on in hot weather long after the engine is shut off. If it's working properly leave it alone(Murphy's law).

On my 94 XJS vert a prior owner had installed a toggle switch to control the auxiliary fan which is mounted next to the steering wheel. Since I have not traced the wiring I don't know where it goes; but I am able to start it when I feel it is necessary. The fan will also run with the ignition turned off. If you want further information I will talk to my technician about it.