May have a frig issue

Hello,

I may have a frig issue but not sure. The frig worked just fine on my last camping trip about a week ago. The frig has been off now for about a week. I went in to check out the trailer. After I turn off the frig, I normally leave the door open. I opened the freezer door today and I smelled an ammonia type smell. I took off the panel to the frig compartment outside but do not see the yellow residue that I have seen mentioned in other posts. Is this a sign that the frig is going?