Staff Answer
Sep 28, 2026 - 07:40 AM
"Back-up" mode means the fridge isn't getting a good reading from the thermistor, so it runs on a timed backup cycle. If a new thermistor didn't fix it, check the connection where it plugs in at the light bracket, and look for a damaged wire between there and the board. If the wiring is good, the optical board is the likely cause. It's discontinued for the N621 now, so the Norcold N7X is the replacement fridge.
If you have any questions, just reach out at info@rvfridgeguys.com or call us at 800-712-8822. You can find everything we carry at www.rvfridgeguys.com.
