Preheat error  

Preheat error

Hello,

My Prusa MK3 display PREHEAT ERROR : the hotend thermisor display the good temperature, but heater don't heat.
The wires is checked and they are all ok. I did replace the hotend heater by a new one, it didn't changed.
The bed work fine. So the fuse 15A is ok (it's the same for hotend heater).

To check thermistor I take the heater block in my hand to heat it with my body temperature. And the displayed value up on LCD screen.

The checking with multimeter is ok.

I tested the global: I disconnected the wires of hotend heater to connect it on power source of 10V DC. The hotend heater did heat and the displayed temperature on LCD screen change as excepted.
So it's as the printer don't sent current in hotend heater...

Reset factory done : no changes
Update firmware done (3.1.1 to 3.2.1) : no changes
PID calibration not done : error THERMAL RUNAWAY (it's logic because heater don't heat)
Temperature calibration not done : 6 steps for bed was done, but the nozzle marked bed and the calibration finish by "crash detected" with SD 0% (but there are no SD card in printer!).

Has you an ideas for me ?

Thanks you

Good day

Loïc