XJ XJ8 / XJR ( X308 ) 1997 - 2003

Cooling fans operation

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Old 04-08-2021, 04:44 PM
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Default Cooling fans operation

2000 jaguar xjr 58,000 miles original owner thank you 😂. What is the best procedure for checking that the cooling fans work properly. Is the fan suppose to run for a bit after you shutdown the engine. Thanks for all your advice. On my 2006 xkr the fan does run after shutdown for a bit.
 
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Old 04-08-2021, 05:47 PM
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The 2000 XJR operates in similar ways to the X300


Both X308 and X300 use a large fan control relay located under the car just fwd of the left front wheel

They are different part numbers and are different and won't work on each other . The X300 is white in color and the X308 is black

If mounted upside down water can get into it ruining it beyond relay repair

The Fans Control Relay is commanded by the Engine ECU which has a 2nd mode A / C load component by a pressure switch

The white wire from the ECU enables one fan ( left ) operation . The white / blue wire enables both fan operation

to test the both fans operation on the coolent tempature mode of operation you would remove the coolant temp sensor connector and put a paper clip in the connector

This is a low current circuit and mimics the coolant going high temp so you will get both fans showing the fan control relay is working properly

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Last edited by Parker 2; 04-08-2021 at 06:30 PM.
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Old 04-08-2021, 07:09 PM
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Thank you so much. Love the jaguar forum. Keep our classics on the road.
 
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Old 04-08-2021, 10:14 PM
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Originally Posted by Parker 2
The white wire from the ECU enables one fan ( left ) operation . The white / blue wire enables both fan operation.
I do not know how the X300 fans operate but on X308, and according to the attached diagram, when the Low speed is switched "on" (via the white wire), both fans run but at about half-speed as they are connected in series to 12V supply (each fan runs at about 6V). When the High speed is triggered (via the white/blue wire), both fans run at full speed as they are connected in parallel to the 12V supply.


If one fan is faulty (open circuit), the other good fan will not run either at Low speed but it will run at full speed.

The fans will run for some time after engine switch-off if they were at High speed at the time.
 

Last edited by M. Stojanovic; 04-08-2021 at 10:19 PM.
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Old 05-21-2021, 04:09 PM
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I unplugged the coolant sensor at the thermostat housing inserted a paper clip nothing happens. Does the key have to be on. My car is 2000 xjr. I did try with key on nothing. One time the fans tried to come on for a second.
 
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Old 05-21-2021, 10:27 PM
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Originally Posted by Sacho
I unplugged the coolant sensor at the thermostat housing inserted a paper clip nothing happens.
You cannot really test the cooling fans operation by shorting the input from the Coolant Temperature Sensor. The sensor is not a thermo-switch but a temp-variable resistor which provides signal to the ECM representing the coolant temperature based on which the ECM, amongst other things, decides when to switch the fans "on". You can, however, test the fans operation by shortening pins of the AC pressure switch connector. See this thread: Fan Control Relay - testing if it's bad? - Jaguar Forums - Jaguar Enthusiasts Forum
 
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Old 05-23-2021, 08:06 PM
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After shorting out the coolant temperature sensor , I now get code P0117 and in restricted performance.
 
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Old 05-24-2021, 09:38 AM
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P0117 means bad connection to the CTS, i.e. open circuit. Check that you have plugged-in the loom connector to the sensor well and that the connector pins are good/clean. If everything is o.k. there, try re-setting the ECU by disconnecting the battery for a few minutes and reconnecting.
 
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Old 05-24-2021, 04:14 PM
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Default Cooling fans

Thanks got the code cleared. Have to make sure it is clipped in all the way top and bottom. Now the low fan does not come on at 194 degrees. Have to put the air on so the fans come on.afraid of overheating. This has been a problem from the start.
 
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