As promised, here are a couple of picture of the car with the body repairs completed. Still working on the fan issue & a few other minor repairs...

 

Thanks, Tom.
Gorgeous! I'm very pleased for you and much relieved.

Gus, I'm wrong about the guide inasmuch as the fuse numbering is perfectly correct and logical: read from top left, work down and across to top right, although there's only 9 out of 11 fuses on the right hand side of the fusebox.

What threw me is that in the fusebox it's reversed: start with #1 at top right, read down then across to top left.

I need to lie down.

Mike

 

So based on the chart assuming it is correct the fuse that is blowing is identified for what function?

 

It's fuse #14, 'Cooling fans parallel', feeds LH fan on full speed via FCM

 

Check your PM

 

At this point I would suggest that you check the condition of the wiring harness and I would assume you have done that and all looked good. If it were me I would test the leads to the control module to see if any of the leads to the fans are shorted. You can do this by removing the plug from the module and fans and use an ohm meter from one pin to the other and ground on both then from one plug to the other if it is all good change the module. My hunch tells me that your fan control module/relay has an issue. I am thinking that one of the diodes has failed and is causing the short.

 

So here are my latest tests and results on my cooling fan issue:

1. I re-inspected the wiring in the area of the fan control module to the driver's side fan and could still find no evidence of crimping or other damage in the harness.
2. I unhooked the driver's side fan connection at the fan. I then checked the wiring from the fan to the fan control module using my multi-meter. This test indicated a dead short - ohm's went straight to 0.
3. I then disconnected the fan control module from the car and ran the same test. This time, there was no evidence of a short - ohms stayed at 1.
4. To make sure that the part I was holding was actually the fan control module, I then ran a continuity test between the orange/yellow connection at the driver's side fan plug to the orange/yellow pin on the fan control module plug. This proved continuity and that I was dealing with the proper wire and had located the fan control module.
5. I then pulled Fuse #14 and verified that with the fan control module removed from the car, there was no short in the "fused" side of fuse #14.
6. Lastly, I tested the pins on the fan control module that would be plugged into the orange/yellow wire & the black wire. Here, I found a direct short.

Based on these tests, is my reasoning sound that the fan control module has internally shorted out as Gus has suggested? If so, is this a repairable part or is one I simply replace?



Problem Identified?


As always, thanks in advance for all of your help!


Tom

 

Also, should I be performing some kind of a test on the fans (particularly the driver's side fan)? These are used replacements that were installed during the crash repairs - could something be wrong with the driver's side fan that caused the fan control module issue?

 

Disconnect the fan then put 12V on it to see if it works or measure the the resistance of the motor. Could be the motor is faulty.

 

Hi Tom,
I think your test #6 nails it to the FCM as Gus said. Jagbits has it listed as part # LJA6702A, but it's a bit pricy. I'd look for one out of a breaker.
If the old one can be dismantled it might be worth having a go replacing the diodes. I can't see anything other than those that would cause a short unless the unit is physically damaged

I'm going to go and sulk now as Gus' hunches are obviously better than my gut feels.

Glad you got there.

Mike

 

Jim & Mike,

Thanks for your feedback.

I did test the fans and found yet another problem. The driver's side fan tested out at .5 ohms. I read in another thread that .5 seemed to be the norm, so I figured that fan was ok.

The passenger side fan tests as an open circuit - no resistance at all.

I tested these at the connector to the fan control module and then re-tested the passenger side fan directly at the fan - same result.

Just because I'm completely ****, I then rigged a 30 amp fused connection from a spare car battery through the fan control module plug directly to each fan, one at a time.

As expected from my first tests, the driver's side fan spun up and ran perfectly. The passenger side fan did nothing at all...

Not sure how these two issues are related, or if one lead to the other, but obviously both need to be repaired.

 

I doubt there's any connection, particularly as the fans aren't the originals.

(sigh) The more you look, the more you find

Mike

 

I would say you need to replace the passenger side fan first before you go any further. Once you have 2 good fans then you can progress.

If you can locate a second hand module get one of those too.

 

Tom, this is late in the game but, do you know how to remove the fans ? If not just ask. It's a lot easier than it looks.

Based.on your tests I bet you are already there, just wanted to offer.
John

 

Ok guys, the saga continues... here's the latest chapter:

I was able to get in touch with my buddy who is a Jaguar mechanic at Chesapeake Jaguar in my area. As luck would have it, he had a spare fan control module.

I went to get it, plugged it in, replaced fuse #14 and disconnected the plug for the bad passenger fan (on the mechanics advice as he felt that the bad passenger fan may still try to start at some point and blow out the new fan control module).

Started the car and within 30 seconds, the driver's side fan came on!

Success, right?

Not so quick. Stopped at the auto parts store for a few bulbs and noticed that the fan wasn't running. Checked fuse #14 - blown again!

Got home, pulled out the new fan control module and tested it for a direct short like the old one - it tests good, no direct internal short.

Then I tested the leads from the fan control module to the driver's side fan - ohm meter indicates a direct short.

I unplugged the wiring at the drivers side fan and test the harness from the fan control module to the fan plug. Short is gone. Plug the fan back in - short comes back.

At this point, here are my thoughts:

• the driver's side fan worked fine at first, now it tests as though it has a direct short
• perhaps I have a direct short inside the driver's side fan when it gets hot?
• the passenger side fan has a bad winding or something that causes it to test as though it is a complete open circuit?

Are these too many coincidences and if so, what am I missing?

At this point, what seems logical also seems like an absurd series of events, I just don't know what else to think!

I have now unplugged the new fan control module so as not to damage it and the junk yard where I purchased the used fans is sending me a new set next week.

Thanks for any thoughts....

 

If you haven't already, check the wiring between the two plugs for a short.

At least now you are getting closer.

 

And they say that Ben Hur is an epic

Knowns:

1) The RH fan is open circuit, but is a separate issue.
2) For F14 to blow, there has to be a problem on the line that it feeds. That line is:

i) The FCM
ii) THe wiring to the LH fan
iii) The LH fan

It's entirely possible that you have been unlucky enough to have two separate problems on the LH fan side with both the fan and FCM. It could be that the LH fan has an intermittent short as you say.

I would hold fire until you get the replacement fans. Test them out of the car first by running them for a while before you fit them.

Mike

 

Jim,

Unless I am missing something, I am pretty sure that the tests that I have done have eliminated the wiring between the FCM and the fan as having a short.

Mike, - waiting for the replacement fans, testing them with a resistance test & a running test outsideof the car and then installing them and the new FCM is exactly my plan at this point.... I‘ll keep you posted.

Tom

 

You know we talk about the wiring and we often forget that the plugs are part of it and could be damaged or cracked. I would suggest looking over the plugs for cracks or the terminals are dislodged. Remember this car took a serious blow to the frontend and anything is possible.

Question, when you are testing the fans are you testing with the A/C on or off? You know that when the A/C is turned on the fans are on.

 

Could you update us on this? What did you find?