The two radiator fans on my '95 XJ6 are running non-stop after the engine is turned off. So much so that it's completely draining the battery. The temp meter on the dash stays right in the proper neutral zone while driving (even on warm days), so the engine doesn't seem to be overheating. Plenty of coolant in the reservoir. It's just the fans seem a bit overzealous about cooling things down after the engine's turned off.

Maybe a bad sensor or relay? Anyone else had this issue?

Thanks!

 

Do you have the JTIS schematics? Do you hve a test light or meter? Are you going to try and fix it yourself? It is almost certainly one of the two things you mentioned and is fairly easily resolved if you have the schematics and tools and desire to DIY- Just check back and several of us can help you.

 

I had same happen on 95 x300.
Turned out to be a faulty relay located behind front bumper on left hand side of vehicle. If you look up from under the car in front of passenger side front wheel (r/h drive) you can see the unit easily. I swapped mine with a used one from the wrecker, and it was instantly resolved.

 

If it is not the relay check the radiator fan switch. When you get under the car it is located to the left side of the radiator. Till then when you turn the engine off, take off one of the fuses for the fans and they should stop working. They are two, 30amp fuses, located on the left box under the bonnet.

 

sparkenzap: I have neither the JTIS schematics nor a test light or meter. If it's a matter of replacing a sensor or a relay, then I'd definitely like to fix it myself.

Urchins: Removing a single 30amp (green) fuse kills both fans, which is what I do every time I stop. ;-)

jagqueen: I'll definitely take a look at the relay.

Thanks, all! I'll keep you posted on what I find.

 

The circuit is pretty straightforward. The temperature switches tell the relays to run high or low. So, either switches or relays can be bad, and the relays are the easiest to change! You can try switching the relay with another to test- just try and get another high current relay which will be the same color as the one you are replacing - assuming the correct one is there now. I don't remember whether the high current rlays are red or black, so hoefully someone else will chime in here.

 

check your thermo switch, that's the normal culprit, its located on the lower left side of of your radiator left plastic cover and water hose, its partially hidden underneath when viewing from the top, the cost of that switch is around $79 contrary to some wild guess opinion, you don't need JTIS or any other testers or schematic diagram, some pretend to know and throw you off course in resolving your issue.

 

Cool wrote
you don't need JTIS or any other testers or schematic diagram, many pretend to know, but are only ego tripping in the disguise of a help.

Your comments above are completely unnecessary and also completely wrong.

1. Anybody who thinks they can can diagnose an electrical problem without a wiring diagram (JTIS Schematic) and a basic test meter is not from this world. If you want to throw parts at your car in the hope of finding a solution then that's your choice but don't advise other people to do it.

2. If your snide comment is aimed at sparkenzap then it is uniformed and rude. I have read many posts by sparkenzap over a long time and he knows what he is talking about and genuinely helps many people. I for one am greatful for his input and for other people like him - you should be too.

 

before you start your bias comment, are you in anyways a jaguar technical specialist? read the problem/ inquiry of armccoy before you write, you do not have to move heaven and earth just to get to that common issue as armccoy have described and actually prescribed by service shop which actually resolves the issue. if your grateful to spark then good for you, that does not mean all have to feel the same as you, keep your gratefulness to a sarcastic guy to yourself as it does not apply to all.

 

I've read the postings in this thread twice. Sparkenzap has been nothing but helpful and even suggested a no-manual-required experiment that might pinpoint the problem. He has helped me umpteen times and never 'pretends' on anything.

As for anyone repairing X300 electrics without a diagram, my hat's off to them. I surely can't.

Cheers
DD

 

WOW, not very um cool, Mr. Cool


I agree with Brendan 100%. You are telling the OP to go spend $79 of his hard earned cash to fix what you think is the problem. Trouble with that is there is a BIG difference between thinking and knowing!

I think that everyone in this thread has read the OP quite carefully. Sparkenzap has confirmed to the OP that the problem could be the thermo switch or the relay and has suggested a no cost way to test which. He is absolutely correct and being completely helpful which you are not.

The only person in this thread who has been sarcastic or snide is you. This is very disappointing as this forum is one of the most congenial and helpful sites out there. Please help us to maintain that kind of environment.

 

My fans run all the time when the ignition is on (from cold). I have replaced the plug to the radiator sensor as it was badly corroded. I thought maybe they failed safe if there was an open circuit. Not resolved. Next I will change the relay as i have just broken a car and have many useful spares! Now to find it! Air con also not working. THere is gas in the system. Could this be connected to the fan problem?

 

But they shut off when the ignition is turned off? If so, that's normal, and the way the systen was designed. The reason is when the fan go into high speed there is a large insrush of current and it would blow the fuse if they went from off to high speed. The solution was to have them run at low speed all the time.

Regarding your AC, have you hooked up a gauge set and measured the low and high side pressures? You might have some refrigerant, but not enough to trip the low pressure switch to engage the compressor. I think you need ~50 psi before the clutch will engage.

 

Thanks. I will look further as on my 94 & 95 cars the fans don't start at all with ignition!
Maybe they are both faulty? On the 94 car only one fan has ever worked at high temp. Other one runs if you hot wire it so maybe change the relay on that car first. Thanks for tip on air con I will add a bit more gas.

I found this comment on another forum!
An early Jaguar technical service bulletin called for mods to the operation of the fan so its normal on early cars for one of the fans to run continuously when the ignition is turned on. There's more info on jaguarforums.com - I found the info there just after I bought my XJR, and it turns out its quite normal!

I also talked to someone who breaks cars and he says some run with the ignition and some don't.
I have done 100,000 miles in my XJ Sport and on that car the fans certainly dont run with the ignition and never have as far as I can remember.

Has anyone got a servive bulletin that covers this??

 

Here: http://www.jagrepair.com/images/TSB/...%20Failure.pdf

 

Thank you so much for that. My XJR is pre mod and still has low pressure switch connected. My Daimler Century as you said works correctly! My XJ Sport has no LP switch and the loop wire but the fans dont run. They do work when hot so as I have done 100,000 miles in the car with the fault and have never blown the fuse I think i will leave as is. A rare case of if it is broken don't fix it!!

 

Do you have your aircon switched on? The fans should come on with the ignition, but only if the aircon is on.
One way to overcome this, rather annoying IMHO, feature is to wire the fan through the relay which controls the aircon compressor clutch (near the screen wash filler in the engine bay). The fans then only come on when they are needed, to help get rid of the heat generated by the compressor, when the compressor is actually working (i.e. the clutch is engaged). Of course, they also come on as needed to reduce coolant temperature, as determined by the thermostat on the side of the radiator.
There is a wiring diagram somewhere on line for this, and it is a 20minute job