Isotherm fridge

[Sparkman]

Hi. Fridge has stopped working. I changed the relay despite it clicking when energised. I have orange box on front of control unit. The relay is slightly warm.fan starts very briefly and stops I disconnected that as it is one of the tests I think no difference. I have green light on control box and did have orange flashing light . I tested voltage at orange box connections it was about 13 v batteries are good. Could thermostats be causing this is it testable? Any suggestions please. Was all working fine until . Engine stopped at sea due fuel issue rectifying that but as said power does not seem to be problem. I’m in southern Italy. I did notice fuse had gone that had been changed prior to testing. In line fuse has small cylinder shape on bottom of holder , what is this.?