E30 M3 water coolant level warning light

[evostorm]

The water coolant level warning light on my E30 M3 comes on from time to time. I've checked the level and that's fine. It's not losing any water at all. I've replaced the sensor with a brand new one thinking that would cure it but it hasn't. When the engine is turned off (with the coolant warning light flashing) and on again the light extinguishes immediately, until coming on again maybe 20/30 mins later.

Any ideas anyone please?

[Mmark]

Short circuit in the wiring?
m

[evostorm]

Good point. I can't see anything but will have another look. Thanks.

[AdamF 88iS]

You either have a short on the check relay side, or you have a broken connection on the sensor side of the system. I would bet that your connector on the sensor is vibrating and causing the connection to momentarily be lost.

[RomanDad]

Are you sure you installed the new sensor correctly??? So the it 'bobs" in the right direction... If not, it will make contact when the car is in motion, tripping th light...