This board is specifically for older style Norcold models with a serial number below 8938727: N640.3, N640.3F, N641.3, N641.3F, N641.3WH, N841.3, N841.3BK, N841.3F, N841.3SS, N841.3WH
If your model has a DC heating element on the back, you have a 3-way style refrigerator. Also, the model number is also stated inside the refrigerator on a decal.