caravan fridge RM4230 not working on elec/12v?

A few weeks ago we changed the heating element on fridge as not working on elec. this solved problem until we went on holiday fridge stopped working again on elec. and also whilst towing not working on 12v. Switched to gas - working fine. Green light is on when plugged into elec., but fridge not getting cold. Red light is not on when switched over to 12v and fridge not working at all whilst towing. Help anyone!