My refrigerator is working poorly. It seems like not enough cold air is getting fromt he freezer to the fridge. So I took the pannel off the evaporator in the freezer to see if there was anything blocking the air flow. There was nothing but I noticed that after I took the cover off and the freezer warmed up a bit the evaporator fan started running much faster. I put it back together and I could now feel more air moving into the fridge from the freezer.

Is this fan suppose to be variable speed or is there something wrong with it?

After putting it back together the fridge worked great for a few days then it started getting warm again.

Thanks
Brad