check engine light

[rick3111]

I pulled the cluster (or tried, need a tip for getting the speedo cable on and off..) on my 91' F250 and saw that there are two engine lights, one yellow "check engine" and one red "engine". The yellow one has never been illuminated, even at start up, what's the yellow one for? and should it come on when key is on engine off?

 

[6 Nebraska IDIs]

The yellow one is for the gasoline engines that came in these trucks. The overlay that has the light sections in it is the same for both the gas and diesel engines.