Hi Guys,

I have just gotten my car back from being repaired by a buddy after a front end collision.






The car now looks great again. The repairs were done by a lifelong body professionally & he has done a great job with everything that I can see. Because he was helping me out, I don't feel this issue is his to deal with..

A quick description of the damage - replaced parts: hood, drivers side headlight, power steering reservoir, core support, fan assembly, core support cover and bumper cover.

I am experiencing a problem with the cooling fans. They are blowing one of the 30 amp fuses located on the driver's side engine compartment. To be specific, the 4th fuse down on the left side of the below picture is what keeps blowing.


I've done a lot of research before posting this - read the related threads on this site, read the shop manual (most of the testing procedures are over my head) and I've looked at the wiring diagram (also mostly over my head).

Yesterday, when the car was hot, I noticed it heating up at stop lights and then cooling back to normal once it had airflow from driving through the radiator. At that time, I diagnosed the fact that the fans were not running and the blown fuse. Trying to diagnose this by myself, I have tried a few simple tests:

• unplugged the passenger side fan and ran the car while hot - same fuse still blows
• unplugged both fans and ran the car cold for a few minutes with the AC on - the fuse did not blow.
• plugged in the passenger side fan and ran the car cold for a few minutes with the AC on - fuse did not blow, fan did not kick on.
• plugged both fans back in & ran the car cold for a few minutes with the AC on - fuse did not blow, fans did not kick on.
• Inspected all of the wiring and connections that I can easily get to, including lifting up the fuse block in the picture above to look underneath - I can find no evidence of frayed wires that might be shorting out.

I've read about a fan control module and relays under the drivers side headlight. I'm not sure how to get to that or what to look for or what tests to run.


Since this problem surfaced, I have asked the body mechanic if he recalled seeing any other issues near the left front headlight cavity - he did not see anything else with obvious signs of needing repair/replacement.


I've only had the car back a few days, but I do know that when I first got it back, on one occasion I did hear the fans running after I turned the car off. The fans were replaced with used parts from 707AutoParts and at this point, I guess they are as suspect as anything else.


I'm pretty handy with mechanical stuff, have a basic understanding of 12v flow, not too good with amps & ohms and am hoping that you guys can give me a hand identifying where the problem is... I do have an electronic tester, but am really a complete novice at using it (including the settings) so please, if you can be descriptive about tests and patient with me, I will try to perform whatever tests need to be done to isolate and repair this issue.


Thanks in advance for all of your help!

 

Ok, a new update. Since my first post, I have tried several other things:

1) reconnected the passenger side fan and disconnected the drivers side fan. I ran the car until it was warm without the AC on and as soon as the Fan Control Module got the signal the turn the fans on, the fuse blew.

2) I was able to watch as the fuse blew this time, and observed it to be a bright flash as it blew out. I guess it's hard to say, but I am assuming this is indicating a dead short?

3) I've looked for the Fan Control Module by removing the driver's wheel well access panel and also the lower cowl cover, but I am unable to identify the Fan Control Module. Even so, while these areas were accessible, I looked for any broken, frayed or pinched wires and could find none. I also saw no additional signs of un-repaired crash damage either...

So it now seems to me that I've removed each fan individually from the system and am still blowing the same fuse. What I don't know is if the passenger side fan will blow the fuse without the AC turned on, I guess that will be my next test once the car cools down enough to unplug the drivers fan and reconnect the passenger side fan. I am going on the assumption (probably wrong) that based on the owners manual indicating that there are (2) 30 amp fan fuses (#12 & #14 if I'm remembering correctly), that each controls one fan unless the AC is on? If that's the case, I'm wondering if leaving the AC off (thus not running the fans together) will allow just one of the fans to work?

Is my thinking correct that only one fan is typically the primary fan and the other only comes on with the AC? If this is correct, which is the primary?

Lots of questions - thanks in advance for any guidance.

Tom

 

If I recall correctly, the fan control module is located near the left side horn and has two relays. One supplies 12V to the fans in series so they run at low speed, the other is a parallel connection and they run at high speed.

 

The relay/module is a TALL looking unit.

Jaguar RELAY MODULE FOR COOLING FANS - LJA6702AA

https://www.amazon.com/Jaguar-Relay-.../dp/B00NB56WY4

The X308 uses the same part so find/borrow one and swap to see if the one you have is damaged.

bob

 

I would locate the relay, and trace the wires from there. The fact that the fuse is blowing when the engine is up to temp suggests that the relay is doing it's job, as in getting the temp signal, and switching power to the fans.

Remove both inner fenders, and trace the wires across the front beam, behind the chrome grill bar, to the fans, and from the fuse box. It would be my bet, that with all that front end damage, and repair, there might be a pinched wire, or a screw put through the harness. The harness travels across that front tube, right on top, where all your damage looks to have been......My 2 cents.....Mike

 

Thanks for the replies... the advice is well received and seems to be validated by my latest "test." I replaced the blown 30 amp fuse, disconnected both fans and ran the car until it got up to temperature. I then pulled over and sat on a road where I could quickly get air flowing into the grill until I saw the slightest hint of the temperature gauge starting to climb above normal. I immediately got air flowing through the grill, (I did not allow the engine to heat beyond normal) and then returned home to find the same 30 amp fuse blown.

In my logic, this seems to eliminate the fans as the culprit, which also means that the problem lies between the fuse box and the harness plugs to the fans. Now that I know what the Fan Control Module/Relays looks like, I can advise that I did find that yesterday and found no obvious signs of damage or wiring issue.

Is there a way to test the Fan Control Module and the relays? This would have to be explained in layman's terms as I really am not a genius with an electrical tester!

Thanks again,

Tom

 

Ouch! I would have likely shed a tear.

Hi Tom,
Fuse #12 (30A) feeds the RH radiator fan directly, and the LH fan through the Fan Control module when the fans are running at half speed.This rules out a short-circuit in the RH fan as this fuse doesn't blow.

Fuse #14 (30A) feeds the LH radiator fan through the Fan control module, but only when the fans are commanded full speed. This is the fuse that is giving you grief.

Sooo, either:
1) The module is damaged.
2) There's a short on the Orange/Yellow wire that leads from the FCM to the Fan, or the fan itself is short-circuit. Your last test rules out the fan.

I agree that the nature of the fuse blowing you have observed indicates a short cicuit (or very close to one!)
The bit we're interested in is attached.

Are you comfortable checking resistance with a multimeter?
You should be able to get the prods into the plug on the FCM.

1) Disconnect the LH fan and measure between LF9-5 and the car ground. It should indicate a high resistance. If not, swop the multimeter wires around and re-measure. If still showing a short, or nearly so, then there's likely a pinched wire as Mike suggests.

2) Remove Fuse # 14, measure between LF9-3 and the car ground. Again, it should read high resistance. If not, swop the multimeter wires around and re-measure. If still showing a short, or nearly so, then the FCM has a problem as Bob states.

Hope this helps,
Mike

 

Hi Mike,

Wow, this is exactly the kind of information I was looking for - thank you so much!

As an electrical diagnostics idiot, I do have a few additional questions that I hope don't sound too stupid...

1) Your test #1 states to measure resistance between LF9-5 and ground. Am I correct in my interpretation of the wiring diagram that LF9-5 is the connector on the end of the wires that feeds into the LH fan and that I should be checking an OY (orange & yellow?) wire for resistance to ground?

2) Test #2 states to measure resistance between LF9-3 and ground. Is LF9-3 the un-powered (fused) post in the socket where Fuse #14 seats?

3) Below is a picture of my multimeter. I've read the instructions for testing resistance, but they are pretty vague. Any guidance on what resistance setting would be correct and what "high resistance" and a direct short would look like on the display?






Thanks again!

Tom

 

RyuTom

Resistance is measured in ohms, the upside-down U shaped character in the 6 o'clock through 8 o'clock positions.

Turn meter on. Set to 6 o'clock 200 ohm position. Touch the 2 test leads together. This represents a short circuit. Look at the display. It may show zero, it may show 0.2 ohms. Either way this is what you will see when you find your short circuit. (FYI, 0.2 ohms represents the tiny resistance in the lead wires themselves).

1) pull the fuse.
2) determine which side of the fuse connections is battery (12volts), which side is the circuit.

2a) set the meter to 20 volts 10 o'clock position. Turn ignition on. Put one lead on a bare metal bolt nearby put the other lead into the left exposed fuse slot. Do you get a 12 volt reading?

If so this is the battery side. If not try the other slot.

Now you know which side provides a path to the battery (12volt side). Turn car off.
Put test lead into other slot.
Turn back to ohms.
Place other lead on any nearby ground, like an exposed bolt, nut screw.
Measure resistance.
If it shows a short circuit (resistance =0) it is showing a short circuit.

If resistance shows open, or a very high number, that tells you the short is in a part of the circuit that is "not in the loop" or not connected right now. This can be on the other side of the relay from a circuit perspective.

I have no diagram in front of me, but I next assume that somewhere between the relay and the fan some part of the circuit is touching ground AKA short circuit.

Let me stop here and give you a chance to ask questions. I hope this helps.

Friend, I'm reading this on a small phone you may have said I forgot. Did you already proven the fan itself works ? I'd unplug a fan and measure the leads to ground. Does one fan show zero ohms on both leads? If so this could help you narrow down your search for the short's location. Unfortunately computer controls sometimes ground both leads intentionally when not in use.

Let us know. I could measure mine if you do find a ground ground on any of the fans connections.

John

 

Hi John,

Thanks for the lesson on using my meter! I will check these things as soon as I can and post the results here.

Thanks again,

Tom

 

To possibly speed things up you can put your meter in buzzer mode, for detecting low ohm circuits. It is at the 5.30 setting, between the 200ohm and ºF positions. You should then hear a sound when you short the probes together. Saves you having to continually watch the reading.

 

Hi Tom,
I can't improve in any way on John's instructions, and just another observation:

From your description, the fuse only blows when the fans are commanded to run. I've looked more carefully at the diagram, and you can ignore test 2 as I see that fuse #14 is only connected to anything additional when the fans are commanded to run at full speed.
You have ruled out a short in the LH fan itself by disconnecting it and still experiencing a fuse blow. This implies a short circuit somewhere on the line marked 9-5 on the FCM.
It could be one of the the suppression diodes inside the module (the symbol that looks like an arrow pointing upward with a bar across). My gut feel, though, is that the Orange/Yellow wire that feeds the LH fan is shorting somewhere.

Easiest way is to pull the plug on the LH fan and put your meter (set on the 200 ohm scale) probes on each connector. I've just checked mine and get no reading (=open circuit:- what you want).

I suspect that you will see a very low reading - less than 0.5 ohms. If so, then you will need to pull the connector to the FCM. If you continue to get a low reading, there's a short in the O/Y wire. If not, it must be the FCM.

Do swop the probes and re-check if you get a low reading with the FCM connected. The aforementioned diode could give you a false low resistance reading, depending on the meter.
Mike

P.S. John: One connection of the LH fan is direct to ground.

 

Mike,

Thanks again. The car is back at the body shop for a few minor touch-up type issues. I will be diving back into the fan problem as soon as i get the car back. This is excellent guidance and i really appreciate all of the help!

 

I'm sure with the collective wisdom of this forum that we'll get to the bottom of this gremlin.

A favour, if I may: please can you post a pic. of your car once you get everything sorted. I'll sleep better with that mental picture rather than the one in your first post.

Thanks,
Mike

 

At this point I would take it back to the guy that fixed it. I assume he got paid buy your insurance for his work? The fans worked before the wreck, now they don't. Should be his issue to figure out. He should figure it out and bill your insurance as this is unforeseen work. I hear ya on the BEST guy ever thing but this is business I feel.

 

Mike - I will proudly post an updated picture of my repaired car as soon as I can!

BRGJag - I wish I felt like I could ask him to do that! The body mechanic (Jerry) is a friend who agreed to help me save the car from the junk yard by putting it back together for me. I bought the car back from the insurance company when it was considered a total loss. The deal was that I would buy all of the parts, and Jerry would do all of the work & paint for a set price. Because this issue goes beyond the scope of our original agreement, I just don't feel it's his issue to deal with.

 

I am a little confused with your fuse location. Look at the fuse chart I have listed for your car on Fig 01.3

Link http://jagrepair.com/images/AutoRepa.../jagxk2000.pdf

Also look at the fuse listing I have from the fuse chart 4-19

Link http://www.jagrepair.com/images/Elec...eLocations.pdf

Looking at the fuse sizes in your photo do not match what the charts show. I could be wrong but it is worth checking.

 

Well spotted Gus.
Must admit I only looked for a single row of fuses that (mostly) matched Tom's picture.

I think that the roadside guide is wrong. If you swop the boxes (see attached) then the match is better - including those with the safety-critical covers.

Mike

 

Ok! When I looked at the wiring diagram it supported the fuse layout. Question what year is your car? I also should have mentioned that I noticed 2 30A fuses for the fans.

Gus
www.jagrepair.com

 

Gus,

I'm not sure what you're seeing. In the picture below, although I'm guessing at the numbering of the fuses on the drive's side engine fuse block, if they are numbered as in the below picture, they do seem to match fuse chart 4-19.



I'm not sure what figure 1.3 shows?

Thoughts?

Tom