Those prices for diagnostics and service are probably the going rate in your area. Automotive rates are also high but RV work is a specialty like sports/luxury car or boat repair. Shop around for better price for replacement fridge if needed. It sounds as if you may not need a new cooling unit or new fridge, may only need to spend a couple of hundred bucks. We have had good service and reasonable labor charges from a local mobile RV repair guy. He works in our driveway, doesn't need brick and mortar repair shop. Meanwhile, invest in a cheap digital voltmeter/multimeter to check 12 volt DC circuits. There should be diagnostic info/advice available in the "tech issues" forum.
