I have a 1997 Taurus that had one of those "Insurance" gizmos plugged into my engine code plug for the past two years, just changed my insurance, (removed gizmo) and now my "check engine light" won't come on. When I just turn on the key, all instrument lights work, but NOT the check engine light. Anyone have any ideas....??

 

If the light worked with the Gizmo in the plug and now won't work, Possible bulb blew. Something else you can try and that is to remove the negative battery cable from the battery post and hold the negative cable end up against the battery positive cable end for 15-20 seconds. This should erase any memory in the computer and may require that you reset the radio stations. Car may idle funny for first few minutes . Take it for a short drive and the computer will readapt to your driving habits etc.