Coolant light flashing

[Walrus]

A few minutes after I start the van the coolant light starts flashing. The top tank is full and the level in the fill tank is between the lines. I've replaced the sensor in the top tank. If I run it for a while the temp gauge goes to its normal level (on or just under the light) and I have heat at the front - where else can I look for the problem?

[marlinowner]

Pull out the coolant level warning "relay" number 42 or 43, if the light still flashes then the fault is probably in the dash somewhere, maybe an earth problem. If it stops the flashing it is probably a bad contact at the plug on the level sensor, although I have also had a dry soldered joint inside the relay which caused the same problem.

[kevtherev]

It will also flash and show slightly high on the gauge if there's a poor contact at the 14 pin connector in the dash.

[Walrus]

I pulled the relay and the flashing stopped, put it back and its stayed stopped! So probably dodgy contacts.