In checking poor low speed A/C performance I readily discovered that the engine cooling fan is inoperative. It's seized solid, in fact. I'm surprised the fuse didn't blow. I am searching for a good used replacement fan.

A few questions. The first two are more a matter of curiosity

1) What are the exact parameters to the cooling fan being turned on? The service manual mentions coolant temp (without stating the trigger temp) and A/C pressure (without mentioning the exact pressure) and transmission temp (without stating the trigger temp). I can't find description/explanation of these details in the manual. Maybe I'm just not seeing them? Meanwhile, in searching (tons of) prior postings I'm under the impression that the cooling fan should simply come on whenever the A/C compressor is engaged. Is that correct?

2) My diagrams do not show a stand-alone cooling fan relay. Am I missing something? Is the relay function incorporated into the control module?

3) In looking for a good used cooling fan I'd like to broaden my search as much as possible. There are several part numbers by VIN break. Is there any backwards/forwards compatibility or are the different versions so different that they cannot be interchanged? I am assuming the later. The one I need would fit from VIN N13293 to N52047.

Thanks
Doug Dwyer

 

Ok, I'm a dumb ***.

The cooling fan is working.

The fan shroud has rigid air vanes...which I mistook for the fan blades. Everyone can have a laugh on me :-)

Any answers to my questions would be welcomed, though. Meanwhile I'll now pursue other possible causes for poor low speed A/C performance. A prior posting has a Jaguar TSB for replacing a spring in the compressor to address the issue. That sounds promising

Cheers
DD

 

Have you seen this troubleshooting guide?:

https://www.jaguarforums.com/forum/s...ol-how-185002/

There are LOTS of possibilities for subpar AC performance. I'd suggest working through the guide, especially to rule out the easy stuff first.

Keep in mind low speed/idle is when the AC system has to work the hardest. Let's say the system is working at only 80% of capability for reasons still unknown. Under most conditions, such as cruising at freeway speed when cooling supply is high (good compressor RPM and lots of condenser airflow), you wouldn't even notice anything amiss. Supply exceeds demand. But when you slow down, compressor RPM and condenser airflow drops. That's when minor issues become noticeable, as the decreased supply is now less than demand. The problem could be as simple as low refrigerant, DCCV not fully closing, a slipping drive belt or compressor clutch, etc.

 

I did see it, yes. Great write-up

Right !

Cheers
DD

 

Check this post out as well:

http://www.jaguarforums.com/forum/s-...ics-faq-55212/