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Marty, European Car Expert
Category: Jaguar
Satisfied Customers: 53942
Experience:  ASE & Bosch Certified Master Tech. Over 30 years experience.
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There I have a Jag xj6 x300 1994. When i turn ignition on to

Customer Question

Hi there I have a Jag xj6 x300 1994. When i turn ignition on to acc position , the engine cooling fans turn on and run in slow speed .Tried turning AC off , but made no difference .Are the fans supposed to run in acc position ? Do you know color coding of fan feed wires from Acc side of ignition switch ? I thought i could swap them over to ignition on side . Is there a better way ? Thanking you very much for any suggestions . Ian Webster
Submitted: 1 year ago.
Category: Jaguar
Expert:  Marty replied 1 year ago.
Hi Ian, the fans should not run when the key is in the accessory position. You should not modify the circuit for the fans to run in the ignition side as this will eventually wear out the fans. The fans should only run when the a/c refrigerant pressure is above 12 bar or the engine temperature is above 88.5 C. There is a thermal switch in the radiator and two pressure switches in the A/C refrigerant line that should be checked. You can disconnect the thermal switch in the radiator. If the switch is bad the fans will turn off when disconnected. I've attached information on the system below. Let me know if you have any questions. Please remember to rate my service in order for the website to credit me for taking your question. Bonuses are greatly appreciated.
Customer: replied 1 year ago.
Hi Marty, Sorry i dont work sundays , Got your answer Mon morning . Tried unplugging engine Rad Sensor , No change . The pic of AC high pressure and low pressure sensors is not the same as my setup .I believe Jag had a big problem with H Pres sensor failing , so cooling fans would not switch on when needed , Jag cut wires off completely on H Pres sensor, and bridged those two wires together . When i unplugged this bridged lead , No fans ! ! If i leave this lead unplugged ,Will fans come on when needed ? From drivers side RH drive on AC line there are two sensors side by side in the same AC line , its the 2nd one in from the side fender . White elect connector . What do you suggest ! Ian .
Customer: replied 1 year ago.
Have you received my response dated 23rd may?
Expert:  Marty replied 1 year ago.
Sorry Ian, I was away yesterday. If you remove the bridge your fans should still come on when the radiator temperature rises but they may not function properly with the a/c on. It would be best to switch the a/c fan on/off with the a/c and have the radiator fan work as designed.
Customer: replied 1 year ago.
Hi Marty , Hope you had a great day off . How do you suggest i re wire AC fans to come on with Air Con when Air Con is turned on . Because Air Con is a Climate control system i leave it on all the time ! ! Air Con does not come on until ignition switch is in Start position . If i could get AC fans to only run when AC is on , Id be Happy ! !
Expert:  Marty replied 1 year ago.
It sounds to me as though someone has bypassed the triple pressure switch. I would start by replacing the switch and reconnecting the wires. Since the fans work with the switch bypassed there is no reason that the system should not function with the switch installed.