Hopefully the bulb is broken on the dash and then you will have to remove dash cluster to replace it. The other is that the circuit is bad and thats why the light does not become lite when the key is on for the initial bulb check.   Its one or the other.

If the circuit is bad we would have to determine WHERE the problem is. If you pulled the dash cluster out. Checked the bulb and and its filement was broken or you tested that bulb in a working circuit...and it did not light...you found your problem..but if it did light..then susprect the powering up of that circuit. You would have to trace the two circuits which power the CEL light circuit and then check their continuity. If they are broken...you would have to find out where on the circuit board that is and solder or splice into repair it. On the other hand if the circuit is intact..meaning its working then the problem is not in the circuit board but the cars wireloom.  You would have to trace back those wires from the circuit board backin the car and find out why it does not work. You can dload circuit diagrams on the internet as to how the dash cluster or cell light is wired.   Backing up a little ..if the dash cluster is defective you can just replace it easily enough.