The frig is a Dometic RM2804. The 12 volt is connected and on. The unit is hot and running on 110 volt. I can hear a sound like water trickling. No cooling at all in side the box. I see no yellow stain, but I haven't removed the unit from the wall. I also do not smell any ammonia. I believe there is no to show the unit it just working. I just bought the rig that was donated to a charity. I was told that everything was working. That was wrong. It had not been tagged sense 2006. I had to pay $1,300.00 for the tags.
Thanks for the help
Gordon