It should snap right into the 3 pin jack using 2 of the jacks pins.
Connect 2 pin fan to 3 pin motherboard.
Desktop board has a 4 pin fan header.
Highly recommend if you need a 2 to 3 pin fan connector.
How to connect a 3 pin or 4 pin fan to the motherboard 1.
Fans and on board fan headers are backwards compatible.
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The fan connector will have two guides 1 and these will need to line up with the tab 2 that is on the motherboard.
When using a 3 pin power connector with a 4 pin fan header the fan will always be on.
Proper fan connector placement is shown in the figures below.
Next press down until the fan connector until it is fully connected to the motherboard header.
A 2 pin fan connector will connect to 3 pin mobo jack if you align the key on the plug little vertical plastic stripes.
The ends on mine are black and not white as shown.
Fan has a 3 pin power connector.
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