Fixed my 'Sword' fan speed controller
Well after several weeks of having nothing but maximum blower speed available I decided it was time to investigate one of the common quirks of the E34/E32 series... the 'Sword' module. As the fans variable speed control would work very occasionally (even if only for a few seconds) I realised that it wasn't a case of blown Mosfet transistors but most likely a suspect solder joint, probably where the connector socket joins the PCB. Well a crook joint it turned out to be, but not the connector. It was a capacitor as marked.
It took a while to trace. I removed the sword module from the climate control box, but left it plugged in. By setting the fan controller about midway and flexing the PCB I could cause the fan to cut in and out. After re-soldering the connector joints I retested it but no joy. Still the same. Finally I pushed a prodded each component on the PCB until I narrowed it down to the said capacitor. The slightest touch to this triggered the intermittant operation. I resoldered the capacitor and VOILA! Sword fixed!!
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