Fridge won't get cold on either AC or propane.

Is the high limit switch the same as the thermofuse? I never saw anything about checking that in the service manual. Also I went out after leaving it on for awhile and the flume was warm by the heating element and the cooling unit was still cold. I will start trying to figure out where the high limit switch is. I pushed the black thing in the middle of the Thermofuse and it did not stay in. It is riveted to the flume.