Re: Norcold Refridgerator
If you tell us which model of Norcold you have, the service manual may give some help. The hum that you hear might be an optional vent fan in the rear of the unit which helps to move air through the flue. Now some questions that may help to get to an answer.
1) what is the model number?
2) how long have you left it on? When left for several hours, does it get cold? and if so, which power sources get cold.
3) do you realize that an absorption refrigerator requires for to six hours to cool to operating temperature? It is especially true of 120V and perhaps a bit longer on 12V.
4) Was it working properly and now quit? If so, how long have you owned it and what is the history?