I know this may sound silly, but I am looking for a failed fan controller. I know a lot of us have replaced them. What I am wanting to do is dismantle the controller to see if I can figure out what is failing. Not 100% sure if I will be able to get into it, but I won't know that until I get one in my hands. So, if you have one that is still laying around, please let me know and we can work out the details.

Hopefully, with a little bit of luck, I will be able to figure out the weak link in the controller and be able to come up with a cheap repair.

 

I might have my original laying around some where, I'll have to look through my parts. I do know that the 2004 module I used as a replacement was exactly the same as the original I removed from my 2003 X. All numbers and ID markings were the same. I think that the module is pretty well sealed so it won't be easy to open without destroying it.

 

Green, I am a submariner, if there is a will, there is a way. Besides, if I can determine even a bad component, I may be able to figure out a way to atleast give the unit some more time. We'll see.

 

drevenak, unfortunately, I don't have a good fan controller. It is appearing that mine is going out as we speak (A/C warms up if sitting at a light for awhile, but temp gauge is still sitting good). So, unfortunately, can't help you there. Part of what I was hoping was I would be able to get a broken one, see what it wrong, come up with a fix that is easy enough to allow anyone to fix their own controller. But, with the slow responses, looking like I may end up using my own for the initial playing, but that is not going to happen until I get the new unit for my own car.

 

If this will help, you will find basically this PWM motor control design imbedded in the propritory sealed unit.



Circuit Explanation:

The 555 IC is wired as an astable and the frequency is constant and independent of the duty cycle, as the total resistance (R charge + R discharge, notice the diode) is constant and equal to 22Kohm (given a frequency of about 1Khz, notice the hum).

When the potentiometer is all up, the Recharge resistance is 1 K ohm (the diode prevents the capacitor to charge through the second potentiometer section and the other 1 K ohm resistor) , and Discharge is 21 K ohm, giving a 5% on duty cycle and a 1Khz frequency.

When the potentiometer is all down, the Recharge resistance is 21 K ohm (the diode prevents the capacitor to charge through the second potentiometer section and the other 1 K ohm resistor) , and discharge is 1 K ohm, giving a 95% on duty cycle and a 1Khz frequency.

When the potentiometer is at 50% , the charge resistance is 11 K ohm (the diode prevents the capacitor to charge through the second potentiometer section and the other 1 K ohm resistor) , and discharge is 11 K ohm, giving a 50% on duty cycle and a 1Khz frequency.

The 555 provide good current capability to drive the mosfet fast and to drive a bipolar transistor.

If you are disgusted by the 1Khz hum of the motor try to rise the frequency out of the audible range (replacing the potentiometer), but remember that at higher frequency inductive reactance of motor rises so the efficiency would drop.

Important:
Obviously the mosfet (or bipolar) must have enough current capability to drive the motor, so the drain (or collector) current must be equal to maximum motor current (at power supply voltage, when it is blocked). The snubber diode too, because it shorts the motor on the off cycle. Both mosfet (or bipolar) and diode have to be hooked (if you don't want them cooked) to a heatsink
if the max motor current is more than 100 or 200mA. I suggest to not stress to much the motor with too much work because it overheats both motor, transistor and diode.

If you don't want braking in the off cycle just place a resistor in series with the snubber diode, it should rise a bit efficiency but have more inertia when slowing the motor down. The value of the resistor must be R=V(breakdown transistor) / Imax, and the power should be 5W. Mosfets have internal zener diode, but don't count on it

 

Colt, thanks for the diagram. I will see if the Jag unit matches up. Odds are, based on what people are describing as problems and what components are likely to fail, odds are, we are looking at a bad bipolar transistor. The rest of the components are low current items and should last pretty much forever. In my case, the fan is getting say a 50% duty cycle signal from the ECU, but, the controller is only outputting say 25% (currently). This is due to the transistor developing a high internal resistance. So, this limits the current and causes the transistor to run even hotter, leading to a more rapid failure of the transistor. So, as long as I can track down a bad controller, I should be able to open it up and troubleshoot the inside.

 

Sorry haven't found my broken controller yet, not sure where I put it. It will turn up one of these days probably when I'm not looking for it.
The reason for changing mine was the fans were not working at all.

 

Green, that is exactly the type of unit that I am after. Troubleshooting mine would involve a lot of having it plugged in to my car with wires extended and what not. Much easier to do one that has completely failed. no rush.

 

Thermo, when I remove mine from my 02 I could easily give it up to you. Right now I have no fans on at all which is what I guess you are looking for. I still need to replace the bad one first, but I will keep it on hand for you if you still want it

 

Also, where did you find your fan controller and how much did you pay? I'm searching car-part right now, but don't know what they call it. Thanks

 

disguay, you need to look for a "fan control module". That should get you what you are after. If you look on e-bay, you can find the controllers periodically. But, in a lot of cases, you also have to buy the fan assembly too. But, of note, just because they are selling the "fan assembly", that doesn't mean that the controller is included. If you are going to buy this way, make sure that you specifically ask a question to the seller if the fan assembly comes with the fan controller. A lot of people have bought just the fan controllers and now people are selling off the fans hoping that people don't ask about the controllers, even though it is the controller that the people are after.

 

Thanks for the help! I will be sure to get back to you with the old one if you still want it. Also I looked into recalls and have created a post about it here... Doesn't really make sense to me https://www.jaguarforums.com/forum/x...all-wtf-56382/

 

disguay, looking on the NTSB website(Vehicle Owners | Safercar -- National Highway Traffic Safety Administration (NHTSA)), they only list 2 recalls that were concerning your year car. One recall was for the parking brake for manual tranny cars. The other concerns the exterior turn signals. It appears what you were looking at was a TSB (Technical Service Bulletin). Now, while these will get you free repairs, normally they are only applicable while you have a factory warrantee on the car.

I don't want to be the bringer of bad news, but this is how the facts are playing out as I see them. TSBs are good information to have available as they can be looked through rather quickly and may give you a quick way to prove your problem. Unfortunately, we (Jaguar forums) have done it the hard way through documenting problems with the cars and what was done to fix them.

 

Thank you for your help thermo. I will get on the problem asap as the summer is coming and i need my fans. Do you still want my broken module.

 

disguay, sure, if you don't want it, I will take it. I want to open one up and see what is making it tick on the inside. Who knows, maybe we can create a little circle of recycled parts for ourselves and keep things going. I know I have a bunch of high current transistors around the house right now, I wonder if they will be the correct ones. may be even able to get something a bit more beefy so we don't have to worry about this in the future.

let me know how much the shipping is and I will make sure to get the money to you.

 

Allright thanks. I still have to swap it out which means waiting for it to ship to me but after that I will pm you

 

I actually hve a used one laying in my trunk right now. I could send it to you if you are intersted. The one that I get off ebay this week has failed again. The fans worked for two days and it croaked so I guess am goin to have to pay the dealership a visit on monday. The only problem is they dont just sell the fan control module I have to buy the whole fan assembly for $556 or something

 

kojo, if the one in your trunk if failed, then I would be interested in it. I'm ironically looking for a broken one, not one that is working. That way I can use my electronic skills, figure out what failed in it and then possibly work out an improvement that can be performed on the controller by most people to make the controller last forever. Part of this controllers problem is that it is located in a harsh environment (back side of the radiator). It gets a little toasty there which is bad on electronics unless they are specifically designed to handle that environment. We'll see what I find and then go from there.

 

I replaced dozens of fan controls and I have the cut up hands to prove it. You can get the module as a separate part.

Here is a TSB from way back.

bob gauff