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Can anyone help ?
During the 2 years that I have owned my X-Type 3.0 automatic it has had a tendency to switch on the cooling fans quite early.
Recently this has become a problem in that once the fans switch on they will not switch off, even at highway speeds.
Then the only way to switch them off is to turn off the engine for a few seconds. The problem then goes away but only for a few minutes.
The fans speeds vary between fast and slow but they do not switch off.
The engine temperature is not excessively high at any time and I know this without relying on the inaccurate temperature gauge.
Thanks in advance
Daviddvm, from the sounds of things, you have a bad fan controller and what you are getting is called "shoot through" of the transistors. In short, the transistors are getting hot enough that they are breaking down and allowing the transistor to conduct even when it isn't being commanded to do so.
Because you have an 03 X-Type, you need to be careful which fan controller you get. There are 2 styles. You have the pre-early 04 style and then you have the post early 04 style. The main difference is the plug that is used to plug it into the car. If you get the post early 04 style controller, you will also need to get the adapter cable to convert between the two styles of plugs.
If you have more questions, let me know. I will assist however I can.
If you find you need a fan controller, give DrDome a forum member a text or a call at 484-903-4813. He parts out X-Types and has a few on hand. I have used him many times for parts. Let him know Vern said HI!
Thanks to all who responded.
Thermo, do you mean that a faulty controller is causing the transistors to get hotter than they should, or are you saying that the transistors are bad and that is why they cannot handle the heat?
How would one test the controller to determine whether it is faulty and would that fault only be present at higher temperatures?
Would on-board diagnostics testing indicate such a fault?
This is a mighty expensive part in South Africa as I believe the control module is not sold separately from the fans. The last thing I need is to fit a new controller only to find that it was not the problem.
It seems to me that fan controller problems are not common so my fitting a used controller may be a low-risk option.
Thanks again.
Daviddvm, I have dismantled a few fan controllers. All of them suffered from a common problem where the transistors that control the fans failed, resulting in issues. In your case, as the transistors start to go, they develop more resistance initially, causing them to get too hot. When they get too hot, their resistance drops significantly and this causes full power to shoot straight through, keeping them too hot and energizing the load (ie, the fans keep running).
In your case, what you would need to do is to first get access to the fan controller. If you look on the radiator wall, just in front of the battery, you will see a silver finned box there mounted to the plate that the fans are on. This is the fan controller. You will need to get that loose so you can access the wiring. You are now going to slide a paperclip along the insulation to the white wire with a blue stripe going to pin 3. ENsure the engine is cold and the A/C is turned off (this includes the defroster, so, just turn off all heating and cooling to the car to be safe). Ensuring that the paperclip will not touch any metal, start the engine. If you connect a multimeter to the paper clip (red lead) and chassis ground (any metal part on the engine with the black lead), you should see 0 VDC. The fans should also not be running at all. You can unplug a fan and stick the probes of the multimeter into the plug to verify that the voltage there is 0 VDC too (anything under 2 VDC is good). As the motor warms up, you should see the voltage on the paperclip take a step jump up to around 5 VDC or something of the like when the fans initially kick on (the motor should also be at mid range temperature wise). You should also see around 7-8 VDC on the fan leads. The paperclip voltage will gradually rise to 12 VDC as the fan voltage goes to 12 VDC. If you see a difference (ie, paperclip voltage is 0 VDC, but the fan voltage is up around 8 VDC for example) then this would confirm a controller issue.
I had a similar problem with my X Type recently in that the fans stayed on after the car was shutdown and I replaced the thermostat and the car returned to normal. It was only marginally too hot, only a couple of needle widths higher than normal, and causing the fans to run on.
I have the same issue. Once the fans come on they will not shut off regardless of the temp - with or without the AC being on. I'm going to replace the controller although my mach. thinks its the thermostat. We'll see...
Last edited by Jag4; 12-17-2016 at 10:13 AM.
Reason: typo
I have this same problem with my GF's '05 3.0, but the fan is on whenever the battery is connected, even when the engine is shut off. Great ideas, thanks for sharing!
Once I've got this fixed, the rest of the car should be good. -jc / az05xtype
I could use some guidance before I make this purchase -
I recall Thermo advised this part comes in two flavors, the 2001 through 2004s, and 2005 and beyond, interface types.
Most replacement parts I find reference the same part number C2S-24957. Some of these are new and come without the accompanying interface harness/connectors
Jag4, because you have an 02 X-Type, you are going to want the controller with the straight fins on it to minimize extra harnesses. That would be a simple unplug and plug in the new (used) unit. If you get the one with the curved fins (like your top link), then you will need to make sure that you get the adapter harness to make it work with your car. The big difference is that the two controllers have different plugs on them which will not allow crossing of new parts with an older vehicle and vice versa.
10-23-2016, 09:26 AM
Cooling fans stay on
