Flashing water temp light

Hi all
wonder if anyone can help with my mk1 rivage cabriolet the water temp light keeps coming on the gauge is fine its just the flashing light on the clocks.
Someone did suggest the sensor in the top of the expansion tank so I have changed that but it still keeps coming on. Someone also mention the number 42/43 relay so took that out to no avail.

If anyone can give me any ideas it would be greatly appreciated

 

Where in relation to the flashing light is the water temp gauge, 3/4, full hot inquiring minds want to know.

What is the level of fluid in the Tank Cold, and hot?

Why you ask? Well because if the tank is the older style it didn't have a air evac hole in the sensor cavity, and if the coolant was below the chamber it would never enter,  and you would have a bubble that could cause spurious low level conditions.

How are your grounds, as the Ground to the Cluster may be corroded and give you a false reading.  Have you tested your Sender?  Have you checked that your Gauge is functional I have how to's int he archive section.

That light flashes because you are either way too hot, or too low on fluid as I have found that if you don't keep the coolant level with the top seam of the tank when cold, then you can get these kinds of issues.  

When was the last time that you changed your t-stat as a partially opening t-stat can cause a over heat.

Do your fans work?  Lots of things to check.

Hi
The gauge only goes up to 1/4 maybe a little more the fluid level is good and the temp gets hot. I haven't checked the grounds (not sure where they are tbh). If by sender you mean the two pronged thing in the top of the tank it has been replaced. Someone also said to try cleaning the sensor on the side of the head, which I have done to no avail. I don't think its overheating unless gauge is faulty. The fans seem to work fine.

In the archive section, I have a plethora of how-to's and gimme's on the electrical as well as grounds.

If you click the link you'll get there.

Sounds as if you have a ground issue as the gauge should be right at the light normally to a little past.

If you aren't running the proper mix of AF to H2O then you can get wonky readings as well.  I have personally have never had a fluid control unit (relay in the fuse panel go in 40 years of these critters) but I suppose it is possible.  

I would lean more to the Gauge being flakey, and a good couple of hours and the use of a soldering iron usually resolves that….but those are usually indications that the gauge isn't working at all.

I had a similar problem with my cabi. If you turn the ignition off then back on again, does the light go away?