B166kel

I'm pretty sure that I have bad connection some where on my air suspension for my cls320 2007 both solenoid or damper valves are not working on my rear left strut it has displayed this with 2 struts so I don't think it's the strut I've checked the connection to the strut and looks fine the diagnostic computer said there was voltage going to the strut. Where is the next place I check the ecu or the control module and dose any body know where they are and which connection will be for the rear left strut or is there anything else i should check
Thanks 4 ur help in advance