Hi Ike Airstream,
Let's try the easy stuff first.
1. Under each sink should be a short pipe wit ha twist on cap (maybe black). This is an anti siphon valve. It is to allow the sink drain water to stay in the trap. If this valve fails, grey water smell will come into the coach. Grey can small just a bad a black.
2. If the toilet has a vent hose, this is a pretty cheap piece of plastic hose. If it breaks black aroma can come into the coach.
3. If all other gas appliances work correctly (double check), this could be low 12 VDC to the fridge. Consider checking the 12 VDC fridge power source after a day of travel. If low, that circuit from source to fridge should be checked.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
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