S80 T6 y2000: Engine Fan Always On

trekking · Post by **trekking** » 07 Nov 2009, 18:10

Hi,

I just had a new problem this morning with my 2000 s80 T6: my engine fan remained on forever after I've turned off the car. This is not the usual let's cool down the motor a bit thing. It was blowing for an hour, in winter, while the motor was already cold. After some hours, if I connect back the battery, it still starts up the fan immediately.

I've seen some related threads for older volvos:
https://www.matthewsvolvosite.com/forums ... hp?t=10667
https://www.matthewsvolvosite.com/forums ... hp?t=11429
https://www.matthewsvolvosite.com/forums ... php?t=6588
but the S80 setup is still not clear to me

I was checking the cables going to the fan: there are two (black-red) bringing ground and 12V, and a 3rd one (purple, I think) that I suppose is the control (see also attached diagrams).

If I disconnect the black-red, the fan is off (obviously, since there is no power going to the fan). If I measure it, there is 12V on the red always, even after the engine was off for hours. This can easily be measured at the 2 pin connector that is positioned on top of the fan unit, in the middle, right in front of you when opening the hood (4/71 on the 2nd attached image). It seems from the attached wiring diagrams that this is normal, but ... Can someone tell me (or help me by checking) whether it is normal? With motor turned off, should there be 12V?

If I disconnect the purple while the engine is off and the fan is going, nothing changes, the fan keeps blowing air. I was reading 0V on the connector. Is this normal? Should the fan spin if the control signal is removed?
According to specs, this control signal "A7" is supposed to be:
#A7 Engine cooling fan (FC) control signal
Pulse width modulation (PWM) signal, Uhigh=0.7*Ubat, Ulow =1.2V, F=100 Hz, Pulse ratio=10%-95%

I think having 0V there could easily be the cause. I understand that this is how the fan speed is controlled, but I don't know what should be the signal when the fan is off! The 2 pin connector (with only one pin used) is on the passenger side of the fan unit. Can someone check this signal for me when the fan is off? (watch out, the fan might start when this signal is disconnected)

Some more info:
- I have no error codes

- The temperature gauge on the dashboard seems to work fine, showing middle (9 o'clock) while I'm driving (am I right, is the the right working temp?) and lower temperatures as the engine cools down. I've also checked with an ELM327 and it was reading values that seemed reasonable.

- Yesterday, while the car was doing its usual cooling cycle after I've turned off the car, the fan suddenly switched to higher rev for some seconds. Than it was back to normal, and turned off after some minutes as usual.

Thanks for any advice,
trekking

Post by **mvsuzr** » 07 Nov 2009, 19:00

I'm not sure from the diagram, but it looks like the 4/71 is the speed control module for the fan. It sounds like the transistors failed and stays gated all the time. (Can this be replaced without replacing the fan?)

Like all other parts, it probably pricey. I wouldn't change it unless you can beg/borrow it off another Volvo owner for a test drive.

trekking · Post by **trekking** » 08 Nov 2009, 11:50

Thanks for the reply! I was checking what that module is, and it the so called FCM (fan control module), manufacured by BOSCH. Mine has the part no. 1 137 328 081 and a quick search gave no results for buying such a thing

Then I was searching a bit more and I found the 2004 FCM recall info (http://www.consumeraffairs.com/recalls04/volvo_fan.html). I was quite sure that my car was on recall, but the description fits on the current situation:

"Volvo is recalling 460,000 cars worldwide to fix the wiring in an electronic control module for the cars' main cooling fan. ... The company said the faulty unit can cause a short circuit in the car's main cooling fan, particularly during slow-speed driving in warm climates. The short circuit causes the main cooling fan to run continuously which, in turn, causes the cooling fan's electric motor to overheat. ..."

Does anyone have more detailed info on this recall? A TSB or something? What was the part no. that was faulty and what was the replacement?

Thanks,
trekking

trekking · Post by **trekking** » 08 Nov 2009, 12:27

Answering to myself since I've found the recall info ... and not one but 3 of them.

1, a TSB from 2002: Recall No. 110 Engine cooling fan, replacement (for some '99 s80)

2, a TNN from 2005: Recall Campaign 141: Inspect/Replace Engine Cooling Fan Control
Module (EFCM) and Cooling Fan Assembly (for 150k volvos, including mine)

3, Service Manager Bulletins Recall 214 : Engine Cooling Fan Module 06/23/2009
I haven't seen this last one, but clearly they still don't know how to make this module without a short circuit

And all this with the“Fixed Right – First Time” slogan ... rather embarrassing.

My recall was the 2nd one, and it was already done.

Post by **mvsuzr** » 09 Nov 2009, 22:49

Thanks for keeping us updated.

I've seen some other questions about cooling fan problems, this is really good info to keep in mind.

Sounds almost like the module's getting too hot, maybe they should move it somewhere else...

Of course, they might just add water cooling, a thermostat, a few valves, and a EFSCCCM (engine fan speed control cooling control module)...

trekking · Post by **trekking** » 01 Sep 2015, 14:19

I've just noticed that I've forgot to post the solution ... here it comes:
The control module is mounted on the fan, but it is a separate module. It is a small box with metal cover mounted at the middle of the fan. It can be swapped with a replacement, just some screws and 1-2 connectors (I don't remember exactly). I've found one in a scrapyard, and after changing it, everything worked fine.

Installation is easy if you have small hands (I think it could even be done in place, although I don't remember exactly) or you have already mastered the way to remove the fan.

To remove the fan: I seem to remember that instructions are to remove it downwards, but I've always done it from the top after removing some of the tubes. When trying to pull the fan up, you might notice that 2-3 mm more space would be needed, and the control module can't easily pass the engine. On my fan, a small 2-3 mm part was cut from the plastic casing, which allows it to be pulled out. I don't know whether it is like this originally or it was done by my mechanic, but it is a really useful mod