Scania 164 480 need info regarding ECU repairers

JJSL:
but the solonoid which receives it’s instructions from the ECU is not sending any electical power signals to activate the solonoids.

How do you know ECU ant sending a signal
Have you traced the live wire back from the solonoid to see where it goes, dose it go to the ECU?
Have you put your mulit meter on the live wire on the solonoid to see if there is any voltage?