bud37 wrote:Source of the post If those CO monitors are 5 years or older they are no longer useable and need to be replaced.Seems to me that on my boat the monitors are wired directly to the batteries( one or the other ) much like the bilge pumps.Check on your safety breaker panel beside the breakers for the bilge pumps, maybe there.Might I suggest a new thread about this, you have 7 pages and hard to check back thru, different subjects......

Thanks Bud, agreed 7 pages was too long to go through, so I am creating a new subject. The CO monitors are brand new, got them last September or October with 5 year life span on them from last year. Under bottom steps there is a co detector breaker location, but I do not think there is any breaker. Looks like a place holder. it looks like a button, but its not. So I think you are right, direct connection to battery. I'll check, not sure why it just went off out of the blue. Unless wire came loose maybe.