I have a 2002 XJR. When I start the car, the cooling fans come on, but only run at low speed. Even when I turn on the AC, they still remain at low speed. This is causing my AC to not blow cold when the car isn't moving. So far, I've checked the fuses and located the relay for the fans, but haven't replaced it. I would assume that if either of those were bad, the fans just wouldn't come on at all. Any ideas on what could be causing this? Any help is appreciated.

 

I know this might be a stupid question but how old is your battery and what is the voltage?

 

Does the AC compressor clutch kick on? I'd think if the AC was kicking in and the fans weren't working then it'd still cool, the fans just kick on high when the AC compressor is running. If the AC clutch isn't being kicked on for some reason, then there could be a higher level cause that isn't sending a signal to turn on the AC clutch, and subsequently the fan hi speed.

If the AC is clutching on, then it should cool. Turn the AC on then watch the compressor, it should cycle between on and off with a frequency of every minute or two or something. Turn cooling to max (min?) to make sure it's being set to turn on. If the compressor isn't engaging at all, then there's another problem. If the compressor is engaging and fans aren't spinning up with it, it could possibly be the relays. But, if the compressor is engaging, and you're still getting warm air, you've got other problems with the AC system.

EDIT: do you have the electrical guide, and the service manual? The electrical guide is available here http://jagrepair.com/JaguarXJ6XJ8Ele...OBDIIcodes.htm

 

Thanks for the responses and insight.

I had the car's battery replaced about 5 years ago. I got a reading of 12.03 volts when I tested the battery, which I thought was normal. Should I start with replacing or charging the battery? The car has mostly sat in the garage with the battery disconnected since I purchased it. I bought it new and it has just over 17,000 miles on it now, so it hasn't been driven much at all since replacing the battery.

I turned the AC to max and the clutch did engaging when I turned the AC, so everything appears to be functioning fine. I don't get any abnormal noises coming from the AC compressor that would indicate any of it's internal bearings are failing or have seized. Since the fans are only spinning on low, and the compressor is engaging, could it possibly be that the AC needs to be recharged? I thought that would be unlikely, but not sure. I'm just wanting to rule everything out before taking it to the dealer.

Thanks for the link to the guide, by the way!

 

See post 8 here for checking for error codes stored in the climate module https://www.jaguarforums.com/forum/x...nfo-faq-66454/ and the first post's links are useful too.

Shop manual here http://www.mediafire.com/file/bu2w7j...hop_Manual.pdf in the climate control description sections, there's flow charts for diagnosing symptoms. Looks like the hot air could be caused by the fans after all, but I only skimmed that so far...

 

Yea battery voltage is low. I would start with the battery first it should be 12.5v