If you grounded the blu wire , you have by-passed the regulator circuit and verified blower motor and positive 12v feed... It is the reg that grounds the blu wire [ neg side of the motor/ a switched ground circuit] when the yellow wire gets a voltage sig from the CP.
So, a meter would be nice , or even a test lamp would help.
You are looking for bat voltage [ 12v] at the plug that goes to the regulator.
This will be the feed side of the plug, not the reg side.
This will be the red/blk wires ....
..then you want to see a lower voltage [approx. 6-8 v] at the yellow /blk wires when the key is on and the defrost position is set.

I am assuming you do have the new reg mounted???