Translation:He wants to find the cause of the problem.
Whenever I see "årsak", "case of the year" comes to my mind :)
German "Ursach" is a useful link.
Is there a way to distinguish he will find vs. he wants to find?
I'm not certain, but I think you'd use skal instead of vil.
What's the difference between årsaken and saken? They both mean the case or the cause, right?