That light is, as you apparently know, NOT a "Coolant Light" but a "Generic Light indicating an issue with engine cooling" light.

The items that I know can light it:

• Low Coolant, High temperature, or a bad sensor falsely reporting either of those.

• Problems with the ECM not 'handshaking' with the Fan Control Module (FCM) - this can include either module being bad.

• FCM sensing current flow to the Fan Motor that is out of specs (too high or too low?)

• Blown Fuse to the FCM.

Other things that might light it:

• Who the hell knows? Our cars are, to some extent, kinda over-designed in some aspects.