Staff Answer
Sep 27, 2026 - 11:54 AM
If you've got 12V at the optical board and it's still dark, that points to the boards. For N621s with a serial below 9126825, the 637779 kit replaces both boards as a matched set. Above that serial, it's the 628974 optical board. Both are discontinued, so stock is limited.
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.
