Why won’t my Volvo EW140B start, and how can I test the actuator?

[Felix Branairos]

I have a 2005 Volvo EW140B wheeled excavator that won’t start at all. I suspect the actuator may be causing the problem. What is the actuator’s function, and what voltage checks should I perform to troubleshoot this Volvo EW140B no-start issue?