The location of the light (below tach.) would suggest that you guys are right and it is the 'fan' icon that ChezChamp is talking about.
Add 50/50 coolant to water mix to just above the full line and it should go away. Contours like to have the resivor FULL and then some. If that does not work the sensor may be the problem, but I would guess that this will solve the prob.
Periodically mine will come on for 30 secs. after start-up then go away. Just top'er off and I am good to go.
