There is very little that can go wrong with the coolant level sensor.
It is simply a pair of metal prongs that project into the coolant.  The
electronic circuitry it is attached to is annoyingly complex and perhaps
inhabited by gremlins.
   Might help to take the sensor out and clean it off.  Be sure you
don't have a big air bubble in that tank.
   For a few weeks about a year ago the light on my 91 would flash for a
minute or so after startup.  Then it cured itself.

Larry A.

Spencer Allen wrote:
> The coolant light in my 85 Westy is flashing long after start up and only
> goes out after the engine has warmed up. The coolant level is OK. Could this be
> just a faulty coolant sensor or something worse? Any ideas appreciated. Thanks
> Spencer
>