Water level/overheat warning

The red LED on my water level/overheat indicator is flashing but there is plenty of water in the system and the fault happens at any temperature (even stone cold)

The sender unit in the header tank has been replaced but the indicator still flashes. I suspect a break in the circuit because I have tried shorting out the sender connector and the indicator still flashes.

I there another feed to the red warning LED that we have missed?

Anyone have a clue?

This has just happened to me.  i took the car to the garage, and he said its prob the thermostat valve that has stuck open.

Kriss,

It happens when it is cold therefore heat is not an issue, plus I changed the thermostat as a matter of course.

Tim

hi what year and what type is your car

My 88 cabrio does this. For a while I could tap the top of the dash and the light would go out. I took it apart but couldn't see any shorts. I'm wondering if its the guage itself.

No, my golf light flashes on from COLD start.  It was left over night and again it happened straight away.  Its booked in to be fixed next Wednesday, but they arte pretty sure its the thermostat valve stuck open.  The water is boiling, but he said just make sure there is water in it and it should be ok.  Worst  things is it could potentially blow the cylinder head gasket  

I'm wondering if its the gauge itself.

If you have checked that the cooling system is OK and the LED flashes continously from turing on the ignition, it is the gauge. Mine flashes with engine not running or when the water is cold.

The other sympton is tapping the top of the dash, this can open or close the circuit to the gauge and thereby start the LED.

This morning I did a full connectivity check on the water level indicator circuit and found that the gauge had failed.

I intend to combine changing the gauge with replacing all the instrument filaments as they often loose their clarity and only cost peanuts but are little sods to change