Is coolant low level warning not a standard option?
 

Just replaced the coolant reservoir tank (along with the water pump, thermo, pulleys and belts). I have a sensor at the bottom of the reservoir but it is/was not hooked up to any electrical connection? Did the connector come apart (and I just can't find the end). OR is this warning/monitor part of an upgraded package that I don't have?

Pretty basic, 04,3.0i

Yeah your sensor is missing/broken/incomplete. They all have it.

Look carefully for the connector. Hopefully it was not torn out.

Thank you, I will keep looking!

I am the original owner, so it should be there somewhere. I assume it warns when tank is empty?

Yeah you do not want to leave that out. It is a small little wire thing with a very small connector. It warns you when the coolant level is low not empty. Low or empty gives the same warning.

I may be wrong but I think only high-cluster dashes (re message text display) have the low-coolant warning. But the sensor was still installed on the expansion tank at the factory regardless if there was a connector or not.

Only vehicles with High Cluster come with the coolant level switch.

I think they all come with switch but just the high cluster vehicles make use of it.

THANK YOU.
I do NOT have high cluster, and the sensor looks like "normally closed" with 2 copper probes that would make continuity through fluid?? and thus if the wire were off I would get a dash warning.

The sensor works magnetically and is not exposed to the coolant. You don't have the wires because you don't have the high cluster.

My sensor is exposed to the coolant. It is twisted into a hole in the bottom of the expansion tank.