Defrost cycle issue - how to force defrost?

[jlatenight]

Hi, the condenser in the inside-back of my bottom freezer compartment is icing over. The heating element has continuity, and I replaced the defrost thermostat thinking that was the problem, but still getting the issue. I guess it’s the control board, but are there any other tests I can do to confirm it? I’d like to force a defrost to make sure the heating element works. How do I do that? Anything else you suggest before I drop $150 on a control board I can’t return? Thanks a ton! -Jon