I've never used a multimeter before, but I can go out and buy one. Is there a chance a fuse can cause this? There is a guy locally selling a module so I don't know if I should go and try another module.

 

Carwatcher, if the fan is turning, then your fuse for the fans is good. Let me get home and I will pull up the diagrams for your car and give you a few points to check. That way you can prove your fan control module good/bad and then you are only having to replace 1 component vice replacing a module, fans, getting a wiring harness, etc.

 

Ok, let me know what to check. I'm hoping I just got 2 bad modules and nothing more serious/expensive.

 

Since your right hand fan seems to atleast have some power (we'll get to the left one in a moment), what I want you to do is to unbolt the fan control module from its mount on the fan assembly. With the controller loose, I want you to find the red wire and the green wires on the control module. Using a straight pin (like what you would use to sew material together), I want you to run it up into the plug along the insulation of the wires (1 pin per wire). Try to position the module so you can get to it in a moment.

Now, start the car, let it idle and put the A/C on max (temp dialed as low as it will go, fan set to max speed). Using the multimeter, put the red lead on 1 of the pins, the black lead on the other pin with the multimeter set to VDC. You should be seeing something right around 12 VDC (possibly a little higher). If you are seeing less than 10 VDC, then this pretty much confirms a bad control module. If you are getting over 10 VDC, then you are looking at a bad fan.

You can repeat this test using the orange/yellow wire and the orange/green wires (ie, orange wire with a yellow stripe or an orange wire with a green stripe). Use the same voltages to determine if it is the module or the fan assembly.

Now, this is not eliminating the ECU from being a problem, but if the ECU was part of the problem, odds are you would be having lots of other issues with the car not wanting to run right along with CEL light.

The other way that you can use the pins is to stick them perpendicularly into the wire till the end of the pin is touching the copper wire inside. Then you can touch the leads to the pins. Either way works. I find sliding the pins up along the wire till they touch the metal contacts in the plug is much easier as you are not having to hold the pins and normally they are making a lot more contact with the wiring. But, sometimes you can only do it by sticking the pin through the wiring insulation.

 

Thanks, I will buy a multimeter and try this tomorrow. One question though, when you say to run the pins into the plug, do you mean where it connects to the fans or where the wire comes out of the module itself?

Edit - I just bought a multimeter...having never used one before, by VDC you mean set it to DC Current Measurement or DC Voltage Measurement...I bought this one if it helps:

http://automotive.become.com/dorman-...s--sc902130462

 

carwatcher, as for the setting of the multimeter, you want to select volts DC. Please do not use the current setting for this. In short, you will get a nice flash from the arc that you will create.

As for installing the pins, it doesn't matter which side of the plug you go on. So, use whatever side is easiest. THe big thing is getting on the correct wires. If you find it easier to access the wires at the fans, then use that point too. It is all the same electrically. I know I am just a little leary putting my hands that close to moving fans.

 

Thanks, I've been quite busy today, so hopefully I can try tomorrow.

One thing I've noticed is that the fans have stopped turning on at all...not when the engine is cold and I put the ac on full blast at the lowest temp, not when I randomly stop and check, and not when I get home and the engine has been overheating. Nothing, before both fans would turn on, then only one, and now neither.

 

Carwatcher, sounding more and more like the fan control module. That's how it tends to fail. In short, the one fan is having to work harder and harder to keep up with the needs of the engine which causes the other half of the fan controller to fail.

 

Dammit, I'm having trouble wit the pins. Can I just unplug the fans and use the multimeter on the connections while the car is on?

 

Carwatcher, disconnecting the plug disconnects the power coming into the control module. So, no, you can't unplug the module.

If you are having issues, just replace the control module and see what you have at that point. The module fixes 99% of the cars. If that doesn't fix it, then you know it is the fans themselves.

 

Ok, so after replacing one bad fan(driver side) and finding another module, I finally got it working...I think. I've driven the car since then a bit and hasn't overheated and the fans have been on just fine(?). When I turn off the a/c the fans don't come on and when I turn the a/c back on they turn on, both fans run at the same speed, they don't stay on after car has been turned off, no more shifting of the revs every 10 seconds while sitting at idle, a/c doesn't blow hot while sitting in traffic, etc. Everything seems good, but...

The only concerns I have is that when the car has been sitting for awhile with the engine running, both fans go to full speed for about 20 seconds and then they go back to normal speed for about a minute or so and then back again to full speed and so on. Shouldn't they stay on at full speed for longer when the engine gets hot? Another concern is that I did the test(full blast fans, lowest temp) again to check the module and the fans are just on at normal speed(I think it's normal speed, it sounds like they are turning faster but look the same to me), I don't feel a blast of air from them. Inside the cabin, the a/c comes on at full speed and very cold, so...I don't know if I'm just imagining things or this module is about to start acting up too.

 

Hey guy's, my module also went bad, don't want to spend the $800.00 from Jag to replace, what is your opinion of using Derale #16749 fan contol with pipe thread probe (wondering if origonal sending unit will do) or #16759 with radiator probe? both have A/C override and are a steal at $43.95 each!

 

You are more than likely going to get an engine code due to the ECU not seeing the controller. Also keep in mind that the ECU controls the speed of the fans by pulsing the fan controller at different rates.