Fan won't stop, need help

I have a Prusa Mendle with a ramps 1.4 board. It's been printing fine for months, but last night the fan stared going full bore, even after a printer reset. Power cycle the power supply, when I turn it back on, the fan goes to full power immediatly. Sending M106 S0 or M107 does nothing. The power draw from the fan seems to keep my heated build plate from reaching temperature unless I just unplug the fan.

I'm looking for ideas as to what could be wrong. my assumption is that there's a short somewhere, but I'm not really that confident in where I should be looking.

Thanks

Is it your extruder fan?

Yes, extruder fan

Figured it out. A small nut had fallen onto the ramps boad and was really hidden from view. it must has been shorting some leads.

so devon jones whereabouts devon you at im in plymouth

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