It said remove screws and push the tab over and be careful of ref line. I was called on the unit .I was not there I just told the tech what to order. I will find out in two weeks when I install the fan. I just thought perhaps someone had run into one of them and could give me some information on what ref line there talking about. After install I will update. Every one of there new units seem a little different ?Or it just could be me .