I have mounted the kit and it works. But I have a question: Is it normal that the led LD2 (Yellow color) a little lighting gifs in normal condition? (Afther 6 sec)
When the switch is ‘on’ the led (yellox color) is lichting normal and afther 6 seconds the led is lichting a little?

Yes, this is normal.

Hi, I too was irritated at the yellow LED not fully switching off.
A quick check of the circuit reveals T3 will possibly not turn off if relay driver has too many volts across it with relays ON current flowing through it.

Leave the circuit values as-is and solder a 10K ohm … 47K ohm resistor (value is not critical) across T3 base and emitter. The easiest way to do this is to solder it onto the resistors R17 and R7, the legs closest to T3.
This ensures the “off” voltage at the base is significantly reduced and yellow LED should now be out.