Thanks for your responses.
MiniPro is running correctly, program Blink is able to manage pin 2 and 3 and activate leds.
With a MySensors Node programme, all is good, and correctly activate when FTDI card is used, Rx and Tx send debbug messages all is correct, Domoticz manage correctlty the node, and drive the 2 leds as wanted.
Problem come as soon as I connect the 230V / 5V module on board : leds are not drived correctly, sometime one is not activate, or desactivate. Only 10% drived correctly.
So my test this afternoon :
If supplying MiniPro by PC via USB and FDTI card provide a good situation, I try to send MY supply (module 230V/5V) to the Vcc pin used by PC (not the legal Vcc input, not the RAW pin) : it's better, 95% drived correctly.
Vcc pin for serial, and Vcc pin ProMini are not the same, not relation with ohmeter...
For connecting earth, I haven't near my heaters. I can try on table to see what's happen.
I will continue, I have to soluce. Best regards.