Its a just a picture... Just to show you which Dummy Load I'm using to emulate current
OK
There was another person on the forum that bought a pack of 10 of them from Amazon and only one of them was good. I do suspect the MOSFET is no good.
you asked what was funny on your first diagram. no need to get rude.
I think the mosfet is not good or its fake. I just made a new purchase from mouser, just tobe sure its the component..
I'm almost sure I've used this exact circuit before and worked perfectlly...
But now, its not. 
But tks a lot, for your help!
Where did you buy them?
Online in Brazil...
@cabecinhas please do not edit your posts as you have done.
As you can see, it makes trash of the comments that follow.
You made some dumb mistakes, maybe, they were questioned or otherwise pointed out, and now you go back and change stuff.
Fortunately you were quoted, and we can see your edits.
a7
What are the values of R4 and R5?
Well the part from Mouser should be good.
ok, sorry for that!
I just don't think its right, someone simply make jokes or anything like that!
I bet most people here are here just trying to learn more, to understand, to impove their knowledges, Am I Right?
Stupid things like that, doesn't help at all!
But tks, for your advice about change topic..
Best.
R4 1k and R5 10K
What is the drain to source voltage when the fan is on?
What is the gate to source voltage?
about 1,2V
Drain to source or gate to source?
Are you sure drain and source are not reversed?
VCC = 12V
@1A >>Drain to Source = 64mV
@1A >>Drain to Gate = -11,9V
@1A >>Gate to Source = 12,0V
@4A >>Drain to Source = 270mV
@4A >>Drain to Gate = -11,58V
@4A >>Gate to Source = 11,8V
This is no good!
With the fan running, attach your BLACK meter probe to 12V, attach your RED probe to MOSFET gate. What is the voltage?
Change your RED probe to the fan + terminal. What is the voltage?
result: -11,82V
Assuming that is the gate to source voltage:
Attach your RED probe to 12V, attach your BLACK probe to the fan + terminal. What is the voltage?
Supondo que essa seja a porta para a tensão da fonte:
Conecte sua sonda VERMELHA a 12V, conecte sua sonda PRETA ao terminal ventilador +. Qual é a voltagem?
hi! 268mV
Sounds OK, how much current is flowing to the fan?