The CO detector usually comes right off the battery cut off switch, I believe, so I think it has an in-line fuse, not through the panel. (Similar to a power front jack or a slide-out, although these may or may not go through the battery cut off switch.)
Try a search for "CO detector" and you'll learn more.
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10