Coolant check light (really beginning to annoy me)

[e30-unit-soldier]

My coolant light comes up on the check computer when the car warms up there is plenty of coolant in there?

Any idea what can cause that to come on?

[Brianmoooore]

Coolant level sensor itself. Small cracks appear in the stem, coolant gets inside, and corrodes the extremely thin wires to the reed switch.
OR one of the two wires to the plug has broken, just where it goes into the plug. Check by pulling each wire gently.
If you get a new sensor, check that the stem is the same length as the original. There is another version of the sensor around, which works the opposite way around to the E30 one. It will light the LED when the coolant is OK, but not light it when it is low, and has a slightly different stem length.

[Cloggy Saint]

Are you saying the light comes on when the car warms up or that there's plenty of coolant in the reservoir when the car warms up (useful things, full stops!). Either way, check the connections and the wiring on the plug that goes to the sender.

[e30-unit-soldier]

Are you saying the light comes on when the car warms up or that there's plenty of coolant in the reservoir when the car warms up (useful things, full stops!). Either way, check the connections and the wiring on the plug that goes to the sender.

Sorry dude for real bad punctuationa˜‘

Light comes on when the car warms up. There is plenty of coolant in the reservoir.