That's a great link, 2oldman. I like the quad fans inserted into the upper vent. My kind of project. I've found my refer, since it's not in a slide, does not require a fan like the refers in kitchen slides do, so mine didn't come with one. But I will probably add two (or four) anyway, just to be erring on the side of caution.
Also, thanks for linking to my RV repair blog post! I added those fans as shown in that 2nd link to my old Dometic '94 refer a couple years ago.
I've already added one fan to my newer Norcold. It also has an incandescent automotive bulb so it's also easy to wire up since it can be done inside the refer. I haven't finished the wiring job on that one so no write up on my blog yet. Soon though.
For anyone with a curious nature, Norcold has a fan kit for installation in those refers in a slide, and you can see how and where they installed it here:
Fan Installation - See page 36I just found this document link. The copy I had was only a users guide...this link is a service manual. Happy I found it so I can add it to my document file.