Fan Blower In/Op

[Defender110]

When you find it Tim let us know, below from Mat's Blog:


mat_fenwick
Posted: Tue Apr 10, 2012 1:18 pm Post subject:

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Just tried to investigate the earth wires but without taking off the dash I can't trace them. They don't go to the earth point on the steering column (as the Haynes states), as that is clean and the blowers still work even when that's removed.

The only other earthing point it could be is m4, described as being 'behind console' and I'm not sure where that is. So I'll just add an extra earth wire for now, and if I ever take the dash out again I'll investigate further then.
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Defender110
Posted: Tue Apr 10, 2012 1:48 pm Post subject:

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mat_fenwick wrote:
but with it being my own car now I'd rather find the problem and sort it if possible). I believe the original earthing point is on the steering column, but will try and trace the wire later today and see what I find. It would seem strange that a connection in the car has suffered from corrosion though...


Yes same as, I have coupled the earth link for the motor to the lighting earth lug but would like to find where the original has shorted out. I assume it is the earthing coneector that has burnt out due to ampage and assume the new temporary earth will eventually do the same??
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Kevan



mat_fenwick

Posted: Tue Apr 10, 2012 7:42 pm Post subject:

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It doesn't have to carry a high current, as all it does is carry the small switching current from the transistor. It does join up with the main earth from the motor(s) though before going to an earthing point somewhere, and my guess is it joins up at the connector to the transistor PCB in the blower housing. That would make sense, both for where the wire appears to lead and also why corrosion/high resistance would be a problem.

What I've done is link to the lighting earth on the blower control PCB - but what puzzles me is why Citroën had 2 separate earth paths. It looks like the original PCB design linked the 2 earths, but the track has then been drilled through to break the link (presumably cheaper than changing the etching). They must have had a reason to do this, but I can't see why!

Anyway, it's working now, with no apparent ill effects.
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[Tim Leech]

I have a plan to bridge the connections 3 and 4 for now or if I get chance rig up an extra earth.

[Mothman]

Did this with my N/A diesel Estate Tim, just bridged the 2 brown wires and the fan worked for the first time for 4 years of ownership. A simple if not the correct fix.
Made life driving her a pleasure i can tell you.

Andy

[Tim Leech]

1 Paperclip and some bluetack later, voila!