A bit of a head scratcher. Engine coolant level low. Has come in a few times, but level is fine. Took expansion tank off. Expansion/header tank is clean and float moves up and own freely. Contact switches from open to close as the float moves. When I jump the connector the alarm goes away. Wondering if it could be a bad connection that comes in intermittently or even deteriorated wiring somewhere down the line.
Before I start digging any deeper, I was wondering if someone had this issue and if there's a known weak spot for this. (I did look through quite a few threads about low coolant level, but most deal with malfunctioning float.)
Thank so much!

 

Only had the switch fall out of the tank so I glued it in.

 

I cut the connector wire and replaced it with a new one (they come with a wire included), and it worked fine. It was the connector. This has happened to me before in another car (an S-Type, with the dual-zone heating flow regulator connector; since I couldn't buy it, I ordered it from the USA, where it is available).

 

Finally got around to changing the connector like you did, even though the old connector looked fine. Cheap fix to, if nothing else, eliminate the connector as the issue. So far the false alarm has not come back.
Thanks!

 

I'm glad, congratulations. They're drastic solutions, but sometimes there's no other option. Connectors deteriorate over time and sometimes only make momentary contact. Besides, I think that female connector is the same as the one on the spark plug coils. But they come in many colors on the market; I used the same color as the original.