I mentioned in another post that my fans don't seem to be operating at all, even after driving and the car (temp gauge) has come up to normal operating temperature. They used to come on with the ignition on and I've read that one fan should come on with ignition on and the second fan kicking in after temp rises sufficiently.

I've checked the fuse, which is ok and am now looking for the relevant relay. Searches suggest that it is up behind the passenger side (RHD) front fog lamp. Any verification? Thoughts?

Everyone else seems to have the opposite scenario with fans running all the time!

Coolant level is fine, with no obvious overheating issues. As an aside, any recommendations/thoughts on a good coolant as I want to do a flush and refill. Is the Jaguar recommended fluid the only way to go?

Thanks in advance.

 

Hello Sogood,

Typically both fans would run all the time with the ignition on, via the white jumper wire on the connector near the firewall. At some point (about 100C) the fans would kick up to high speed as controlled by the coolant temp sensor, on the lower left side of radiator. But that generally doesn't happen in cool weather.

That temp sensor could be faulty, or the relay of course. I've heard the relay is down where you say in front of the left wheel. I can't come up with a mental picture of the circuits, but you should be able to test and trace the power to the fans through the fuse, relay and temp sensor. Those are the usual suspects.

No comments about which coolant to use. Others will.

 

My manual says "below left side headlamps" so you might have to set your sights a little higher to find it. I thinking it'll be below, and just forward of, the bank of relays that are located just aft of the left headlights. It should have eight wires and should be bigger than the usual relays as it's actually two or three relays (and some diodes) all incorporated into one 'module'.





Many cars were treated to a modification (described in a Jaguar bulletin) that changes the entire operating scheme of the fans. I always forget the details. The bulletin has been posted several times. If you dig thru enough cooling fan threads I'm sure you'll find it.




FWIW ....

I don't recall what the Jaguar recommendation is but when I bought my X300 (at 30k miles) it was filled ordinary old fashioned green anti-freeze and that's all I've used ever since

Cheers
DD

 

Relay is here

 

BOTH fans run TOGETHER!!!!

Low speed = fans are in SERIES.
High speed = fans are in PARALLEL.

Check the fuses and wire harnesses.

I uploaded these TSBs to the large file area YEARS ago.

bob gauff

 

Thanks to all for the input and to b1mcp, as a picture says a thousand words. I will be looking into it tomorrow and will update. I read that one fan comes in at "warm" and the second follows when things get hotter. We shall see.

 

Well, what you read is just plain wrong about the fans. And, BTW, I am sure bob will be wrong one day, but I don't think it has happened yet. The reason most of us know about both fans running in series and parallel is that it caused a blown fuse problem if they started in high, and the aforementioned bulletin was a fix.

 

Well, I had a look see at my inoperative fans today and still no joy. Both fuses are ok, and I swapped the working relay from my donor car. What an odd place to put a relay!! (I found that popping the fog light out, gave me a better view of things.) Still no change. I let the car idle, up to and well beyond normal operating temperature, sill no joy.

I have the option of swapping the sensors and/or the fans themselves ( bless you donor car!) but before I go there I wonder if anyone knows am I missing something. Surely one of the fans should work? Or does the "first" fan determine the operation of the "second" fan? Seems odd if that is the case.

Changing the sensors means I will have the opportunity to do a coolant flush and change also.

Any thoughts appreciated.

 

You need to carry out some tests of power and ground with a Multimeter (you can get basic cheappies on ebay for a tenner). Without that you could spend a lot of time switching parts and still not find the problem.

As a start point, check for power and ground on the top fan multi plug. Power is a direct feed from the fuse, ground is switched via the relay. If you have power and ground here then the fan is probably dead - but make sure no issues in plug itself.

If you don't have power (purple wire) and you are sure the fuse is good (did you check with a tester or just visually?) then you have a fault in the wiring.

If you don't have ground at the fan connector and you are sure the relay is good (probably if you have swapped them) then check connections at back of relay. You should see have power on Yellow/White wire and Ground on Black.

The Yellow/White power at the relay comes from the shorted connection for the AC switch as mentioned in previous posts.

If all of those are present, the fan should run.

 

You are right that one fan can affect the other when in the initial "series" mode. Kinda like the old Christmas tree light string when one bulb fails.

 

Thanks for all the useful input folks. And to b1mcp, I do have my trusty multimeter, fuses check out fine. I even replaced them, ( 30 Amp x 2 in the front passenger side, engine bay fusebox ) just to be sure. I will check the actual wiring and see what, if anything, I come up with.

It's disconcerting to know that you can drive your car with or without fans and see no discernible difference whatsoever on the "temperature gauge"!

Thanks again and watch this space.

 

Always dangerous to be dogmatic about Jaguar setup as they do vary across different markets.

My UK spec X300 was standard with no modifications made to the cooling fans. Typically the fans would not run on startup or at low ambient temperatures. They would run at low speed in warm weather but only very rarely at high speed in England. Ireland won't be much different.

As has been said earlier, the fans always run together either at low or high speed.

I've come across a few in this country which have been deliberately modified to operate permanently low speed/high speed whenever the engine is running and can see this would be advantageous in hotter parts of the World.

Jaguar temperature gauges are designed to stay in the middle unless a serious overheat occurs. Absolutely useless!

Graham

 

Well, thankfully, that didn't take too long. Back in from the shed now after following b1mcp's suggestions. Pulled the top plug and had power and ground on it. So, I disconnected both plugs and removed the fan assembly. Easy job, just two 10mm nuts at the top corners and the bottom of the shroud sits into three metal clips on the lower radiator support bracket.

I then put power directly to the top motor and zilch! Nothing doing. However, the bottom motor ran fine, so it seems as its' dependent upon the top motor working?

Whipped the fan assembly out of my donor car, popped it in and het presto! I have fans!

They both come on with the ignition switched on, so maybe the modification was done at some time in the past. I'm not sure, but I do remember they operated the same way on the donor car also. I know the modification is done at the sensor ( I think) but either way I'm happy.

Running all the time as opposed to not running at all is much more favourable. They do stop running when the ignition is switched off, so that's good also, but they would probably continue to run on for a bit if the engine was hot. We shall see. As an aside, like almost every other xj6, my splash shield is missing from underneath, but I am thinking about making up a cover of sorts, at least for the front corners. The amount of water and gunk that splashes up in there, all over the fog lamp connector and fan relay is unreal!
Thanks again for all the input.

 

Yah my splash gaurd is toasted

 

Hi All,

I have the same issue with my car.

Both fans were running ok with the ignition on.

But the upper fan was very noisy. I removed it to investigate what was going on and try to fix it. I wanted to remove the blades the investigate the electrical engine. But I was not carreful enough and mullered it with a hammer because it was very rusty... Fan blades were rotating OK by hand and I put it back in place waiting for a new part to arrive.

But now, none of the fans are working !

I have checked for power supply and it seems OK.

• Ignition ON, I find 25V for the upper one between the conectors solots.
• 13 volts for the lower one.
• No power to the lower one when the upper one is disconected.

Can you confirm me that the power supply is OK ?

If one fan is dead, then none of them are working ? Am I correct ?

Thanks in advance for the help ! I was extremely frightened when I saw the engine temp rising with no limits .... But apparently no damage to the headgasket...

Best regards
Julien

 

Just took my 1995 Jaguar XJR 52K miles out of winter storage and after the first drive, upper radiator fan would not shut off even after 4 hours. Disconnected the battery and charge it. Fan came on as soon as I reconnected the battery and again stayed on after driving until battery was disconnected. From my research on the Forum so far looks like one of 3 possible problems 1) bad fan control module, 2) bad fan relay or 3) bad temperature sensor. or? Can anyone help/tell me how to isolate the the failed part?

 

I finally got the new relay and surveyed the various methods one could get to it. Taking
off the wheel well cover seemed to be one option and taking off the plastic shield residing
underneath the radiator seemed to be another. After a few exploratory "feels" I found an
opening that was large enough to get my arm through and reach the suspect relay. Once
found it was an easy operation to pull the relay down off it's stalk, remove the plug and
install the new relay on the plug and test for proper fan operation. Eureka! it works!

 

You did install a white colored X300 fan control relay module ?

A black one for the V8 powered X308 is different as the fan system has a slight difference