1984 Tiffin Allegro AC issues

Tiffin used Dometic(Duotherm they were called back then). 30 year old AC, you are better off just replacing it with a NEW 15k model. Yours is 13.5k as they did not have 15k models back then. It is a straight change out. Just get the complete NON ducted inside control and upper unit. You can use either Dometic or RVP( Coleman). The roof top 14 by 14 inch square hole and wiring accommodates both. Just make sure that when you remove the OLD unit you do NOT tear the Metal roof. If someone has siliconed the old AC to the roof(BIG no no), getting the old gasket loose will tear the metal roof unless you gently take your time and scrape the old gasket OFF. The foam gasket, even if NOT siliconed will still be stuck to the metal roof, and can also tear it unless you take your time and gently scrape and release the gasket. Doug