Fan ressistor c5 2009

[Sufii]

Would be good if the fan doesn't have to come out!

Something tells me that you have done that before? haha
Really dont hope the fan has to be replaced, its no space down there.

[white exec]

Not on C5, but chunks of dash out is a bit daunting if you haven't done it before.
A bit of practice here on XM: heater matrix, instrument panel, switchgear...

[Sufii]

Not on C5, but chunks of dash out is a bit daunting if you haven't done it before.
A bit of practice here on XM: heater matrix, instrument panel, switchgear...

Aha , but its not an dash out job here on this car. You can access it from the footwell from drivers side.

[Paul-R]

If you bridge the two thick wires of the plug that goes on to the resistor and the fan then works then it's not a fuse fault and, further, all wiring works as it should. The engine has to be running though for the fan to operate.

Actually, can I modify that. Bridging the two thick wires will still show the fuse and fan motor to be working but it doesn't necessarily implicate the "resistor".

The control unit isn't actually a resistor as such but does control the voltage/current applied to the fan motor. It responds to instructions sent to it so it could be fine but just not being told what to do. I suspect that you need to get the car read with a Diagbox to find your way through this.

[Sufii]

But if I bridge them two and use it a temp fix ?
So you mean that it can for example be the Climate control module that is broken? Even if the light and the buttons seems to be working? Correct me if Im taking wrong og misunderstanding.

[Paul-R]

You could use it as a very temporary "fix" I suppose but full strength for the blower is quite intense. I think you would get tired of this very quickly!

I am unsure of the exact route the instructions flow from the controls. I think this is something that Marc may be able to help with.

[white exec]

The module in question is not just a resistor, but an electronic module which varies the voltage applied to the fan motor, and hence controls its speed. By bridging it out it is possible to ascertain that the fuse/supply is ok, and that the motor will also function (at full speed). If this works ok, it is sensible to replace the control module ("resistor") with a decent quality new one.

These modules are obviously under considerable electrical strain, and are prone to failure. Replacing with cheap pattern parts is probably not a good idea. Note that they are located with their cooling fins in the ducting airflow, for self-preservation, which gives a clue to their indifferent design. It will help extend their life if the cabin fan is not left switched to high (or high-ish) setting, so that they don't have to operate at high current delivery when suddenly switched on - which I suspect is approaching 25A on full fan speed.

[GiveMeABreak]

I believe the OEM Hella (BEHR) Blower Control Modules are 28A Chris, so not far off. It's another reason why I suggested an original OEM part for these - expect to pay around the £50 mark for a genuine new OEM HELLA BEHR one outside the dealer network.

The actual Blower motors themselves are approaching 30 Amps - fitted to the larger models like the C5 and C6, I know the original OEM Hella (BEHR) ones are 356 Watt and probably follows that the Magneti Marelli ones are at least this, so 30A if my calcs are correct. Part 6441AJ. Still I would be surprised if the actual blower motor is faulty.

[Sufii]

I buought one pre used, but it was testet and working from the guys who sild ut to me. Part number was 6441AJ from Behr.

[Sufii]

Ok guys, tried to jump cable between these two point as Paul recomnended. And the fan is working on full speed! Thats a good sign.
But what know? Should I buy a Brand new ressistor? With ort number 6441AJ?

[Sufii]

It worked!!!
.
I made that jumper, and then let the fan blow on full speed for 30 minutes, after that I gave it a try with my old ressistor. And everything worked just fine! You guys saved me this winter! Thanks

[white exec]

Always good to have a winter jumper handy when the temperature drops

[Paul-R]

Just be prepared to go through this process again if the fan stops. After a while you'll be able to get the "resistor" out in well under 5 minutes!

As a matter of interest do both the old and the new control units work now?

[Sufii]

Just be prepared to go through this process again if the fan stops. After a while you'll be able to get the "resistor" out in well under 5 minutes!

As a matter of interest do both the old and the new control units work now?

But why does this happen? What can I do to prevent this to happen?

[Paul-R]

I don't know. I have to do it every so often to my car - it's actually stopped working at the moment and I'm looking for a good day to "go through the process".