I have an absorption type fridge and have replaced the cooling unit after 6 years. We are full timers. We too noticed the temperature increase when the sun was on the refrigerator side of the coach and finally last fall it failed completely. The cooling coils were very hot on the lower part of the cooling system and the ice maker shut down because the ice box was not cold enough.
Fix was not cheap and should not be attempted by a do-it-yourselfer.
Bob & Joan Alexander, 2010 Tiffin Phaeton 36 QSH, 2013 Jeep Wrangler (toad)
Lobo & Juniper (woof, woof)