BX Ventilation fan

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oilyspanner
Posts: 1246
Joined: 26 Oct 2003, 16:08
Location: United Kingdom
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BX Ventilation fan

Post by oilyspanner »

Hi all, I have a problem with my ventilation fan on my new TZD PreviouslyI have cured these by replacing controller cards, fan motors and the transistor thingy in the fan housing, what I am looking for is fault finding to shorten the replacing time,
Symptoms: no fan at all, no click from relay on steering column
fan turns freely with no bearing play.
Thanks BX Gurus out there
Stewart
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AndersDK
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Joined: 21 Feb 2003, 04:56
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Post by AndersDK »

Stewart -
Have you tested the fan in fact runs well directly off a +12V feed ?
The fan has a constant (fused) +12V feed - and speed is controlled on it's LO side (earth connection) - either by the transistor module acting as a variable resistor - or the relay connecting directly to earth.
The panel speed control module should bring the fan on any LO speed by transistor module - or full speed by relay. Even if relay does not work - the variable lo speed panel control should still work.
As the speed control is 100% depending on the earth connection - you may simply have a problem in the circuit's earth connection.
I suspect this may be the multiplug earth connector found somewhere under the dash.
On LHD vehicles - this earth block is found on the steering coloumn - no idea where it's located on RHD vehicles.
Ooops [:I] had to edit this submission - as I got mixed up with LHD/RHD above [:o)]
DLM
Posts: 524
Joined: 13 Aug 2001, 03:01
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Post by DLM »

My BX fan is currently intermittent (but in a predictable way) due to some form of bad earth/connection at the card or its connectors - though backlights remain on. It MAY be be worth checking to see if gentle pressure on either the knob or its backplate makes any difference. Apart from that I'd certainly go with Anders' suggestion about trying a direct 12v feed to the fan motor, which has saved me a lot of time and trouble before now.
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