New build not working


 
I can't tell from the pic of both diodes have the bar toward the edge of the board? I see some poor soldering across the board, particularly on the oscillator and in that are in general, but seems unlikely to cause your blower problem (alone).

I would suggest that you use a multimeter and test continuity on the wires you are using in the CAT5 cable for the blower power and ground to see if they are connected pins on the HM board CAT5 jack "Blow" and "Gnd" respectively. (test with the power disconnected from the HM) Would be a shame to trouble over something so simple as the wrong wires...
 
Both diodes have bars that go towards the edge of the board.

I tested with the multimeter to ensure the CAT5 wiring and it is correct. But what I also noticed was that there was momentary continuity between +5 V (Pin3) and Ground (Pin 4). I'm thinking that this maybe the reason why the blower stays on, even at 0%.

What do you guys think?
 
That's normal... must be a capacitor charging up because you will get a blip of continuity one way and then a blip of continuity the other way if you reverse the leads. Not your issue....

The first thing I would do (after resoldering your oscillator and doing general soldering touch up across the entire board) is change your blower mode in your HM config to PULSE, this eliminates the need for the feedback circuit which reduces down the blower drive circuit significantly. If your blower starts working now then you have an issue in your feedback circuit.

Next thing I would verify the label on the large MOSFET (prob need a magnifier for this), it should say FQU 11P06

Then verify the transistor right above the large MOSFET says BS170

verify the value of the few components surrounding the above MOSFETs (resistors, diodes etc)

It in not impossible that a part got mixed up by you or a supplier, so verify to eliminate that possibility.

I would clean up the solder on the above mentioned transistors as I can see solder extending out over the board beyond the limits of the trace and possibly in contact with other traces

I would also clean up the solder on the CAT5 jack as the same problem exists... I can't quite tell of the solder from the +5v pin is touching the Blower pin? At any rate, reflow the solder there so it is confined to the trace area around each pin.
 
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