Heater blower Fan stuck on full max speed D9. The solution

[neildavies]

Not a question, but I thought it might help if someone does a search in the future.

Please note this onlyaffects D9 models (1999 onwards)

Suddenly on the weekend, my heater fan stayed on full, regardless of what was displaying on the climate control display. I did a bit of research, and eventually I found it to be a(nother) common 406/C5 fault. The problem is a "control module" which obviously controls the fan.

The problem part is a small black box located under the passenger footwell, right behind the heater (centre console). It has 2 green plugs going into it.

Remove the cover under the glovebox to gain access to the dashboard from the footwell.
Unplug the 2 green plugs.
Undo the self tapping screw and pull the black box downwards.
Attached to the top of it is a 3" long heat sink.

As Haynes would say, fitting is reversal of removal.

The part you're after is 6441L2 and costs £52 at the moment.

I placed as many word in the title for future searches.

I hope this can help someone one day. I forgot to take photos sorry, but it's an easy job
Neil

[steve_earwig]

Nice one dude, nice helpful post too.

[Welly]

Excellent!

[Tim]

Does this only affect D9 406's?

My S reg 2.1TD has recently developed the same problem - it started when I switched the AC off and the heater blower jumped to max and is stuck there. Is the fix the same for the pre-face lift model or is it a different problem with the same symptom?

Thanks!

Tim

[neildavies]

I can't remember what it is now, but there is a different solution for D9's. Another box, but I'm not sure if it's on the fan itself.

Don't go taking things apart on this advice though, have a search on the internet.

[mjb]

With the D8 it could equally be the control module attached to the blower, the loom, the climate control display unit or one of the many interior sensors. The only time I can remember it happening on a D8 was a long time ago and I think it was the temperature sensor located in the passenger footwell near the centre console. IIRC that only affected 'auto' mode though.

If it happens regardless of manual fan setting, it's likely either the control pcb on the blower or the display. I'd re-plug the connectors first though - both the blower motor one and the one behind the display - because it costs nowt to try