Problem with cold water coming in

I am having a problem with the cold water coming in. The hot water works just fine. My washer only has cold rinses on all the cycles so when it gets to the rinse cycle, it just hums. Also, there is no cold water mixing in with the hot water for the wash cycle. We have checked both ends of the hoses and they are not stopped up. My husband even changed our water valves going out to the washer but it still didn’t help. What do you think could be the problem? Would it be a mixer valve, water inlet valve or what. Is there something we can test to make sure?