Hello. The cooling fun control module for my Jaguar X Type 2004 model got burnt inside. I replaced with another one I got from the scrap yard but still funs couldn't work. Later I got another one from a similar vehicle which is running but it could not work on mine. When I connect the funs directly to the battery, they work. What could be the problem? I am asking for help

 

Muzunga, sounds like you either have a bad connector at the fan control module or the ECU is not telling the fans when to turn on.

Please keep in mind that your fans do not run any time the engine is running. They are controlled via the ECU as to when to run. So, if your motor is cold and have nothing else on in the car, the fans are going to be still. What I would tell you to do is to get into the car and turn the key to the RUN position (do not start the engine). Get into the A/C controls and turn the fan on to the highest setting it will go and dial the temp till it wil go no lower. Now, start the car with the hood open. If you put your hands on top of the high beams and lean in over the engine, you should feel a strong breeze blowing against your face. If you feel a light breeze, then your fan has issues.

 

Muzunga, it sounds like you have a wiring problem and we will need to do some troubleshooting to figure this out.

Before we get going too far, Hopefully you are aware that you have a unique beast in that your car was manufactured with 2 possible wiring harnesses and some of the parts for your year car are different. So, before we get going too far, you need to look in the driver's door jam and look at the build date of your car. The magical date is March 2004. If your car is built on/before this date, then you have the earlier "2003" wiring harness and if it was built after that date, you have the "improved wiring harness". This is a factor with your problem as the improved system got a different fan control module. Now, the plugs are different atleast for the power and signal coming in. So, putting the wrong controller in is not possible without installing an adapter. You will find that you may get asked a lot of questions at the parts counter about your car as they are trying to figure out which version you have.

I am going to make an assumption that you have atleast a little bit of knowledge on how to use a multimeter. So, the first thing you want to do is unbolt the controller so you can get better access to it. You should see 2 plugs going to the controller. 4 large wires (running to the fans) and 4 other wires coming from a harness that runs into the engine. We are only interested in the harness that goes into the engine bay at hte moment. So, the first thing we are going to do is disconnect this plug and look at the connectors. they should be fairly silvery in color. If they are dark in color, that is a problem. this is where using some contact cleaner is going to be helpful and you may have to get a fine scraper and rub the connectors to get them back to a silvery color. May want to look at your controller and verify those terminals too if you find these discolored. If you did find them discolored, then remake the connector, set the controller off ot the side, and start the car and dial the A/C to make to see if the fans run. If they do, problem solved. If not, turn the car off (place A/C back to an OFF condition too.

Next step is to electrically check controller. For this, you may need to use a straight pin to slide it down next to the wiring so you can make electrical connection. Some multimeter leads have special probes that will have this pin on the end already. But, first check is to put the multiemter to read resistance (the 2M, 200K, 20K, 2K or the funny looking O). Touch the leads together to make sure you get effectively a 0 reading (should read around 0.6 ohms or so, this is normal). You are going to touch the red lead to the black wire going to the controller (may need to use the pin) and the black lead to any part of the car that is metal (battery terminal is right there). The multimeter should read within 1.0 ohm of your initial reading. If not, your ground wire has an issue and you need to make repairs to that. Next, turn your car on to the RUN position, but leave the engine off. Now, locate the white wire with a green stripe. Set your multimeter to check for 12 VDC. Measure between the white/green wire (red lead) and any metal part of the car. Did you get 12.4 VDC or higher? If yes, then this wire is good. If not, then you have a high resistance in this wire and you are loosing your power to the controller. repairs to this wire will be needed. Next move the red lead over to the brown wire with the green stripe. Again, check for 12 VDC on this wire. Did you get 12 VDC? If yes, the wiring is good. If no, need to fix this wire.

Assuming all is good to this point, you are going to need to access your ECU (under the cowl on the right side). What you are going to do is start with the engine cold and prep as much as you can (so, having a second pin may be advisable). What you are going to do is measure for 12 VDC at the white wire with a blue stripe at the controller with the engine running and the A/C on full blast (fastest fan speed, lowest temp). You should see something in the neighborhood of 12 VDC. The actual value is not so important as long as it is up around 10 VDC, but write down the number (or atleast remember it for the next 30 seconds). Now, you are going to go to the ECU and find the white wire with a blue stripe (Pin 51 on the 2003 style car, Pin 44 on the 2004+ car) and measure that voltage. It should be pretty close (within 1.0 VDC) of the reading at the controller. If you got a difference between the two readings and the controller was reading down around say 5 VDC and the ECU end was up around 10+ VDC, then you have a problem with the wiring. If the controller was up around 10 VDC and the ECU end was down low, then you were measuring the wrong wire, but you should still be good as the controller end had a good reading. If you have 10+ VDC at the controller end for the white/blue wire, then double check the white/green and the brown/green wires for 12 VDC. You may find that one of these is now reading low (under 12.0 VDC). IF so, replace the associated fuse first and if you continue to have a low voltage, then you have a wiring problem with that wire.

Now, assuming you have done all these checks and all the wiring is checking out, This really only leaves 2 components left that can be bad. The controller and the fans themselves. So, keeping an eye on the engine temp (may need to turn off the car and let it cool), use your multimeter to measure between red wire (red lead) and the green wire (black lead) to see if you are getting about 12 VDC here. You should repeat the checks on the orange/green wire (red lead) and the orange/yellow lead (black) for 12 VDC. Both of these should show power when you have the engine running and A/C on full blast. take note, this connections should be big enough that you can slip the tips of the multiemter leads into the plugs. But, if you need to use the pin like before, go for it. If you are getting 12 VDC to the fans and they are not running, you have bad fans. If you are not getting 12 VDC, then you have a bad controller.

If you have any questions, ask. Some people play with electricity every day, some don't. This is low voltage, so, the problems you are going to run into are minor in nature. But, I also want you to feel safe and confident in what you are doing. the bigger hazzard with this is the fans suddenly kicking on and having your fingers in the way. So, keep things clear of the fans whenever possible. The fans have the potential to kick on even with the car off. I am minimizing this chance by having the car cold and only turning on the A/C for short periods of time.