a yellow thermometer
It's no cage it means either low coolant or to have the coolant system checked
Engine coolant.
Low coolant warning
It means your coolant levels are low.
In a 1999 Ford Mustang GT : The low coolant light is in the lower part of the dash just to the right of the " BRAKE " warning light ( it kind of looks like an " X " INSIDE of a box )
it looks like a little coolant jug that comes on the bottom left side of the dash
check antifreeze level
You need coolant. This happened when my water pump went bad and I needed to refill the coolant.
Vehicle Coolant (Antifreeze) and i would put some in soon before major problems.
The light will be on the left side of your dash. It will look like a box with a wavy line towards the top (to reperesent a liquid)
There is the ( low coolant ) warning light that is at the bottom of your gauge cluster between the engine temperature gauge and your tachometer
Coolant level warning light. It is either your coolant warning light, wiper fluid warning light or low tire pressure warning light.