On my 99 blazer, lately I noticed that the check engine light does not come on all the time when the key is turned to the on position as it should till you start it. It's not on while driving or running, but I thought it should come on EVERY time the ignition is turned on with the other guage lights. Thanks for any help

 

A bulb test should result in the check engine light being illuminated. Sometimes you can skip over the bulb test if you twist the key straight to the 'start' position.

 

Even leaving it in the on position doesn't light the light