My information called it an SES(service engine soon) lite. The voltage for the circuit goes hot when you turn the key on, the computer controls the ground. I believe fuse 4 for the gages in the IP fuse box is for that circuit. The bulb may be bad, the fuse might be bad. If you check the fuse, check the terminals where the fuse plugs in, one of the terminals should be hot with the key in the run or crank position. Even if the circuit is hot, the lite won't work without a ground. The information I looked at was for a C1500 98 chevy.

I've seen older vehicles where that lite wouldn't work, I hooked a scanner to the data link connector, just to see if I could communicate with the computer.

 

Thanks guys,

So the " service engine soon" lite should come on when ignition is turned to the on position.

Will check it out in this truck.

Thanks again,

 

The SES light should go thru what is a called a "bulb check" which turns the light on briefly after a key cycle so you can tell if you have a burned out warning lamp.
I have seen unscruplous people remove the bulb and resell the vehicle rather than make a necessary repair.

 

thanks zx1100f1

that is what i am concerned about. I want to know all systems are go and the lite did not come on.

Will pass on this truck.
thanks,